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Aminergic signaling is known to play a critical role in regulating female reproductive processes in both mammals and insects. In Drosophila, the ortholog of noradrenaline, octopamine, is required for ovulation as well as several other female reproductive processes. Two octopamine receptors have already been shown to be expressed in the Drosophila reproductive tract and to be required for egg-laying: OAMB and Octβ2R. The Drosophila genome contains 4 additional octopamine receptors-Octα2R, Octβ1R, Octβ3R, and Oct-TyrR-but their cellular patterns of expression in the reproductive tract and potential contribution(s) to egg-laying are not known. In addition, the mechanisms by which OAMB and Octβ2R regulate reproduction are incompletely understood. Using a panel of MiMIC Gal4 lines, we show that Octα2R, Octβ1R, Octβ3R, and Oct-TyrR receptors are not detectable in either epithelium or muscle but are clearly expressed in neurons within the female fly reproductive tract. Optogenetic activation of neurons that express at least 3 types of octopamine receptors stimulates contractions in the lateral oviduct. We also find that octopamine stimulates calcium transients in the sperm storage organs and that its effects in spermathecal, secretory cells, can be blocked by knock-down of OAMB. These data extend our understanding of the pathways by which octopamine regulates egg-laying in Drosophila and raise the possibility that multiple octopamine receptor subtypes could play a role in this process.

The female locust lays its eggs deep within soft substrate to protect them from predators and provide optimal conditions for successful development and hatching. During oviposition digging, the female's abdomen is pooled and extends into the ground, guided by a dedicated excavation mechanism at its tip, comprising two pairs of specialized digging valves. Little is known about how these active valves negotiate the various obstacles encountered on their path. In this study, female locusts oviposited their eggs in specialized sand-filled tubes with pre-inserted 3D-printed plastic obstacles. The subterranean route taken by the abdomen and digging valves upon encountering the obstacles was investigated, characterized, and compared to that in control tubes without obstacles. Data were obtained by way of visual inspection, by utilizing cone beam computed tomography scans in high-definition mode, and by making paraffin casts of the oviposition burrows (after egg hatching). We demonstrate, for the first time, the subterranean navigation ability of the female locust's excavation mechanism and its ability to circumvent obstacles during oviposition. Finally, we discuss the role of active sensory-motor mechanisms versus the passive embodied function of the valves, central control, and decision-making. [ABSTRACT FROM AUTHOR]

AbstractEgg-laying is one of the key aspects of female reproductive behavior in insects. Egg-laying has been studied since the dawn of Drosophila melanogaster as a model organism. The female’s internal state, hormones, and external factors, such as nutrition, light, and social environment, affect egg-laying output. However, only recently, neurobiological features of egg-laying behavior have been studied in detail. fruitless and doublesex, two key players in the sex determination pathway, have become focal points in identifying neurons of reproductive significance in both central and peripheral nervous systems. The reproductive tract and external terminalia house sensory neurons that carry the sensory information of egg maturation, mating and egg-laying. These sensory signals include the presence of male accessory gland products and mechanical stimuli. The abdominal neuromere houses neurons that receive information from the reproductive tract, including sex peptide abdominal ganglion neurons (SAGs), and send their information to the brain. In the brain, neuronal groups like aDNs and pC1 clusters modulate egg-laying decision-making, and other neurons like oviINs and oviDNs are necessary for egg-laying itself. Lastly, motor neurons involved in egg-laying, which are mostly octopaminergic, reside in the abdominal neuromere and orchestrate the muscle movements required for laying the egg. Egg-laying neuronal control is important in various evolutionary processes like cryptic female choice, and using different Drosophila species can provide intriguing avenues for the future of the field. [ABSTRACT FROM AUTHOR]

Squamate reptiles are central for studying phenotypic correlates of evolutionary transitions from oviparity to viviparity because these transitions are numerous, with many of them being recent. Several models of life‐history theory predict that viviparity is associated with increased female size, and thus more female‐biased sexual size dimorphism (SSD). Yet, the corresponding empirical evidence is overall weak and inconsistent. The lizard Zootoca vivipara, which occupies a major part of Northern Eurasia and includes four viviparous and two non‐sister oviparous lineages, represents an excellent model for testing these predictions. We analysed how sex‐specific body size and SSD is associated with parity mode, using body length data for nearly 14,000 adult individuals from 97 geographically distinct populations, which cover almost the entire species' range and represent all six lineages. Our analyses controlled for lineage identity, climatic seasonality (the strongest predictor of geographic body size variation in previous studies of this species) and several aspects of data heterogeneity. Parity mode, lineage and seasonality are significantly associated with female size and SSD; the first two predictors accounted for 14%–26% of the total variation each, while seasonality explained 5%–7%. Viviparous populations exhibited a larger female size than oviparous populations, with no concomitant differences in male size. The variation of male size was overall low and poorly explained by our predictors. Albeit fully expected from theory, the strong female bias of the body size differences between oviparous and viviparous populations found in Z. vivipara is not evident from available data on three other lizard systems of closely related lineages differing in parity mode. We confront this pattern with the data on female reproductive traits in the considered systems and the frequencies of evolutionary changes of parity mode in the corresponding lizard families and speculate why the life‐history correlates of live‐bearing in Z. vivipara are distinct. Comparing conspecific populations, our study provides the most direct evidence for the predicted effect of parity mode on adult body size but also demonstrates that the revealed pattern may not be general. This might explain why across squamates, viviparity is only weakly associated with larger size. [ABSTRACT FROM AUTHOR]

BACKGROUND: The pea leafminer, Liriomyza huidobrensis, is one of the most important insect pests on vegetables and ornamentals. The survival and egg‐laying behavior of leafminers are markedly affected by the environment temperature. However, the mechanisms underlying the relationship between egg‐laying and temperature are still largely unknown. RESULTS: Here, we find that leafminers have evolved an adaptive strategy to overcome the stress from high or low temperature by regulating oviposition‐punching plasticity. We further show that this oviposition‐punching plasticity is mediated by the expression of pyx in the ovipositor when subjected to disadvantageous temperature. Specifically, down‐regulation of pyx expression in leafminers under low temperature stress led to a significant decrease in the swing numbers of ovipositor and puncture area of the egg spot, and consequently the lower amount of egg‐laying compared to leafminers at ambient temperature. Conversely, activation of pyx expression under high temperature stress increased the swing numbers and puncture area, still resulting in a reduction of egg‐laying amount. CONCLUSION: Thereby, leafminers are able to coordinate pyx channel expression level and accordingly depress the oviposition. Our study uncovers a molecular mechanism underlying the adaptive strategy in insects that can avoid disadvantageous temperature for reproducing offspring. © 2024 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Species‐rich semi‐natural grasslands have been lost during the last century due to agricultural intensification. This has had large negative consequences for many specialised species, including grassland butterflies. To prevent further loss, management regimes in the remaining grasslands must maintain habitat quality over time, and we therefore need to understand the habitat preferences of specialised species and how different management regimes affect their survival.We studied the egg‐laying preferences of the threatened marsh fritillary butterfly in relation to host plant properties, microclimate and management (grazing) on Gotland, Sweden. Moreover, we followed the survival of eggs and larvae from 27 egg batches during a period of 8 months (from June 2020 to March 2021) in grazed and ungrazed areas.We found 92 egg batches in total and the average number of eggs was 184.5. Egg‐laying probability increased with increasing host plant size and abundance, and environmental variables associated with a warm microclimate (low grass cover, low vegetation height and south‐facing edges). The 27 egg batches that were followed over time had on average 203 eggs in June. Roughly 28% of the eggs developed into larvae, and about 17% of these survived over the entire study period, resulting in an overall 4.7% survival. Egg survival was higher in ungrazed habitats compared with grazed; in March (post‐hibernation), there were almost nine times more eggs in ungrazed habitats.This study highlights the complex habitat ecology of specialised butterflies and underscores the detrimental impact of intense grazing, advocating for rotational grazing or mowing regimes. [ABSTRACT FROM AUTHOR]

Despite the challenges posed by multi-drug resistance in synthetic anthelmintics, the potential of plant extracts as an alternative helminth control option offers a ray of hope. The current study, conducted with meticulous care and thoroughness, delves into the anthelmintic activity of crude water and ethanol extracts of three plant species, Andrographis paniculata (Hempedu Bumi), Azadirachta indica (Neem), and Litsea elliptica (Pawas), against the nematode, C. elegans. The preparation of water and ethanol extracts from the three plants involved maceration and ultrasonic methods, respectively. Phytochemical screening was conducted to identify the active compounds in both extracts, followed by determining the total phenolic content (TPC) and total flavonoid contents (TFC) using the corresponding Folin-Ciocalteau and aluminum colorimetric methods. The percentage yields of water extracts were 15.10%, 13.11%, and 9.55%, and ethanol extracts were 9.78%, 2.94%, and 15.50% for A. paniculata, A. indica, and L. elliptica, respectively. All extracts tested positive for alkaloids, steroids, terpenoids, protein, and carbohydrates. In water extract, A. indica exhibited the highest total phenolic (TPC) and total flavonoid (TFC) contents of 58.38 ± 0.005 mg GAE/g and 18.68 ± 0.005 mg QE/g, respectively. In contrast, in ethanol extract, L. elliptica exhibited the highest TPC and TFC of 122.67 ± 0.398 mg GAE/g and 96.69 ± 0.027 mg QE/g, respectively. L. elliptica ethanol extract appeared to induce the most pronounced effect on reducing head thrashing activity compared to other extracts in C. elegans. Both water and ethanol extracts of A. indica and L. elliptica exhibited significant mortality in all examined concentrations with maximum mortality. [ABSTRACT FROM AUTHOR]

Stick insects (Phasmatodea) have many different oviposition strategies, reflecting a range of adaptive behaviours and morphologies to best place and secure eggs in their environments. Oviposition strategies in Aotearoa New Zealand phasmids are not well documented, but the literature so far suggests that they drop individual eggs to the ground from their position in the foliage. Here, we present evidence for an oviposition strategy unique among the Rō stick insects of Aotearoa New Zealand. Individual female Spinotectarchus acornutus were observed inserting their eggs in a range of substrates, in particular the bark of trees and in spaces within the textured surfaces of tree fern trunks. We also highlight how the specific morphology of their eggs may be an adaptation to assist in substrate attachment, while their elongated secondary ovipositor could aid in egg insertion into substrates. [ABSTRACT FROM AUTHOR]

Since widespread monitoring began in 1976 in the UK, habitat‐specialist butterfly populations have declined dramatically. The main driver is habitat degradation, caused primarily by land‐use change, perhaps interacting with changes in vegetation phenology.Here, we focus on two declining species: Boloria selene (Dennis & Schiffermüller) and Boloria euphrosyne L., Lepidoptera: Nymphalidae. We hypothesise that these species differ in their preferred breeding habitat, and this is driven by differences in their temperature preferences, mediated by vegetation cover.We use mark‐release‐recapture techniques and oviposition observations to characterise and compare adult distribution, habitat use and oviposition site preferences of the two species.Egg‐laying females of both species are shown to occur in areas with relatively high abundance of the larval food plants, Viola spp. (violets), principally V. riviniana, and they oviposit where Viola spp. abundance is locally high. However, in contrast to B. selene, ovipositing B. euphrosyne tends to occur in areas with relatively short and sparse cover of vegetation.B. euphrosyne oviposit in sites with a relatively high plant surface temperature irrespective of ambient temperatures, in contrast with B. selene in which the temperature of oviposition sites increases as ambient temperature increases. These differential temperature strategies likely underlie differences in breeding habitat preference.Microclimatic cooling caused by increased vegetation growth in spring may be one reason B. euphrosyne is declining in the UK, while both B. euphrosyne and B. selene may be affected by declining Viola spp. availability. Our data provide further evidence that drivers of butterfly declines can be multi‐factorial, and paradoxically, that thermophilic species do not necessarily benefit from climate warming if responses of other species result in cooling of their habitats. [ABSTRACT FROM AUTHOR]

Background and Research Aims: Little information exists on the breeding behavior of the Andean Condor (Vultur gryphus). Its global population, estimated at 6700 adult individuals, is declining throughout its distribution range. With less than 150 condors, the Endangered condor population in Ecuador is of conservation concern. This study aimed to analyze the breeding behavior of wild-born Andean Condors in Ecuador. Methods: Between 2009 and 2021, we monitored 22 egg-laying attempts in eight Andean Condor nests, evaluated the parental care of three breeding pairs of condors and recorded the species' interactions with other raptors and mammals during the nestling-rearing season, and examined the breeding success of an Andean Condor pair during a decade of monitoring. Results: Our breeding records indicated that Andean Condor lay eggs throughout the year, and 16 nestlings spent between six and 10 months in the nest before making their first flights. We found differences in the length of time that the parents remain with the nestling, and described agonistic encounters between condors and other raptors and a Spectacled Bear (Tremarctos ornatus) in the condor nesting areas. The breeding success of the monitored condor pair was 0.88 nestlings per clutch, and the female laid an egg on average every 15 months. Conclusion: Considering the small size of the Andean Condor population in Ecuador, studies on the breeding behavior of wild-born condors are a high research priority to assess population trends and prevent extinction. Specifically, we recommend further research on parental care, breeding success, nestling survivorship, and nesting phenology. Implications for Conservation: Beyond the importance of the protected area system, strategic planning of key areas for the maintenance of condor populations in the northern Andes must encompass the evaluation of new potential protected areas that offer direct benefits to these birds. These should include nesting sites in human-dominated landscapes such as rural Andean areas. [ABSTRACT FROM AUTHOR]

Tetranychus urticae, a prominent pest mite in strawberry and vegetable cultivation in China, has developed escalating resistance due to extensive chemical pesticide application. Consequently, there is an urgent need to identify safe and efficacious methods to reduce resistance development. In this study, 38 commercially available plant essential oils (EOs) were screened for their acaricidal potential and ability to inhibit oviposition. The findings revealed that 13 EOs exhibited notable acaricidal activity, with lemon EO demonstrating the highest toxicity, followed by sage, patchouli, frankincense, lemongrass, palmarosa, and oregano EOs. In addition, 18 EOs displayed significant inhibitory effects on oviposition, with lemon EO exhibiting the highest inhibition rate (99.15%) and inhibition index (0.98). Subsequently, sage, frankincense, clove, lemongrass, oregano, patchouli, myrrh, black pepper, palmarosa, and geranium EOs also showed inhibition rates exceeding 50%. Despite black pepper, clove, myrrh, and oregano EOs demonstrating relatively low toxicity against T. urticae, they exhibited heightened efficacy in inhibiting oviposition and suppressing population expansion. This study conducted a comparative assessment of the acaricidal and oviposition inhibition activities of EOs and their principal constituents, thus providing a theoretical basis for the development of botanical acaricides against T. urticae. [ABSTRACT FROM AUTHOR]

Aminergic signaling is known to play a critical role in regulating female reproductive processes in both mammals and insects. In Drosophila , the ortholog of noradrenaline, octopamine, is required for ovulation as well as several other female reproductive processes. Two octopamine receptors have already been shown to be expressed in the Drosophila reproductive tract and to be required for egg-laying: OAMB and Octβ2R. The Drosophila genome contains 4 additional octopamine receptors— Octα2R , Octβ1R , Octβ3R , and Oct-TyrR —but their cellular patterns of expression in the reproductive tract and potential contribution(s) to egg-laying are not known. In addition, the mechanisms by which OAMB and Octβ2R regulate reproduction are incompletely understood. Using a panel of MiMIC Gal4 lines, we show that Octα2R , Octβ1R , Octβ3R , and Oct- TyrR receptors are not detectable in either epithelium or muscle but are clearly expressed in neurons within the female fly reproductive tract. Optogenetic activation of neurons that express at least 3 types of octopamine receptors stimulates contractions in the lateral oviduct. We also find that octopamine stimulates calcium transients in the sperm storage organs and that its effects in spermathecal, secretory cells, can be blocked by knock-down of OAMB. These data extend our understanding of the pathways by which octopamine regulates egg-laying in Drosophila and raise the possibility that multiple octopamine receptor subtypes could play a role in this process. [ABSTRACT FROM AUTHOR]

Gravid female stable flies, Stomoxys calcitrans (L.) (Diptera: Muscidae), oviposit in many types of organic substrates, including animal feces, but there is limited information as to which factors mediate attraction and oviposition. Here, we (1) tested effects of oviposition site moisture and odor on attraction and oviposition by flies, and (2) selected a highly effective oviposition site (fly rearing medium) to determine the key constituent(s) that mediate(s) attraction and oviposition. In moving‐ and still‐air olfactometers as well as large laboratory rooms, we show that (1) odor and moisture of oviposition sites play distinguishable functional roles in the close‐range attraction of gravid female flies and their propensity to oviposit, (2) rearing medium containing fish food, wheat bran, wood chips, and a watery solution of ammonium bicarbonate [(NH4)HCO₃, releasing NH3 and CO2] is a more appealing oviposition site to female flies than is cow feces, (3) ammonium bicarbonate in this medium is the key constituent for stable fly attraction and oviposition, (4) NH3 alone or in combination with CO2, but not CO2 alone, attracts stable flies and induces oviposition, and (5) NH3/CO2 and fish food in combination are more attractive than NH3/CO2 or fish food alone. With fecal bacteria reportedly emitting NH3, and with stable fly larval development reportedly reliant on (fecal) microbes, it follows that gravid female flies may be guided by airborne microbe‐derived cues originating from prospective oviposition sites. Isolating these microbes and identifying their odorants could enable the development of a synthetic odor blend which, coupled with NH3 and CO2, may prove highly effective as a trap lure to capture gravid female stable flies. [ABSTRACT FROM AUTHOR]

Photoperiod is a key environmental factor in regulating bird reproduction and induces neuroendocrine changes through the hypothalamic-pituitary-gonadal (HPG) axis. OPN5, as a deep-brain photoreceptor, transmits light signals to regulate follicular development through TSH-DIO2/DIO3. However, the mechanism among OPN5, TSH-DIO2/DIO3, and VIP/PRL in the HPG axis underlying the photoperiodic regulation of bird reproduction is unclear. In this study, 72 laying quails with 8-week-old were randomly divided into the long-day (LD) group [16 light (L): 8 dark (D)] and the short-day (SD) group (8 L:16 D), and then samples were collected on d 1, d 11, d 22, and d 36 of the experiment. The results showed that compared with the LD group, the SD group significantly inhibited follicular development (P < 0.05), decreased the P4, E2, LH, and PRL in serum (P < 0.05), downregulated the expression of GnRHR, VIP, PRL, OPN5, DIO2, and LHβ (P < 0.05), reduced the expression of GnRH and TSHβ (P > 0.05), and promoted DIO3, GnIH gene expression (P < 0.01). The short photoperiod downregulates OPN5, TSHβ, and DIO2 and upregulates DIO3 expression to regulate the GnRH/GnIH system. The downregulation of GnRHR and upregulation of GnIH resulted in a decrease in LH secretion, which withdrew the gonadotropic effects on ovarian follicles development. Slow down of follicular development and egg laying may also arise from lack of PRL potentiation to small follicle development under short days. [ABSTRACT FROM AUTHOR]

Brood parasitism by cuckoos relies on manipulating hosts to raise their offspring and has evolved stunning adaptations to aid in their deception. The fact that cuckoos usually but not always, remove one or two host eggs while laying their eggs has been a longstanding focus of intensive research. However, the benefit of this behavior remains elusive. Moreover, the recently proposed help delivery hypothesis, predicting that egg removal by cuckoos may decrease the egg‐laying duration in the parasitism process caused by biting action, lacks experimental verification. Therefore, in this study, we examined the effects of egg removal/biting on the egg‐laying speed in the common cuckoo (Cuculus canorus) to experimentally test this hypothesis. We compared the duration of cuckoo egg‐laying in empty nests, nests with host eggs, and nests with artificial blue stick models to test whether cuckoos biting an egg/stick can significantly hasten the egg‐laying speed than no biting action. Our results showed that biting an egg or an object is associated with cuckoos laying approximately 37% faster than when they do not bite an egg or an object. This study provides the first experimental evidence for the help delivery hypothesis and demonstrates that when cuckoos bite eggs or other objects in the nest, they lay eggs more quickly and thereby avoid suffering the hosts' injurious attack. [ABSTRACT FROM AUTHOR]

The major insect pest of soft and stone fruits, the spotted-wing drosophila, Drosophila suzukii , has evolved a greater preference for laying eggs on ripe fruits over fermented ones. In a recent study, Cavey et al. found that higher responsiveness to low sugar concentrations has had an important role in this evolutionary shift in egg-laying behavior. [ABSTRACT FROM AUTHOR]

The importance of Muscovy ducks in industrial poultry production is growing; however, little is known about the physiology of their reproductive cycles. This study investigated the influence of male biostimulation on female ducks before the commencement of the laying phase. A total of 30 muscovy ducks, hatched in the same year at 289–341 days of age, were divided into two groups of 15 birds each and kept with and without contact with a male duck until the day of first egg-laying—319 ± 14 and 335 ± 13, respectively. Before reaching egg-laying maturity, the cloacae of 29 adult ducks were subjected to daily clinical assessments. The evaluations yielded four unique categories of outcomes, determined by assessing factors such as the degree of redness and protrusion of the mucous membrane, the moisture level, and swelling of the cloacal sphincter muscle. The results of this study on biostimulation revealed that, on average, female ducks that had contact with males laid their first egg 16 days earlier, weighing 78.7 ± 3.0 g, compared to the isolated female ducks, weighing 79.1 ± 7.0 g. Furthermore, there was no significant difference observed in the mean initial egg weight between the groups (p = 0.841). The cloacal morphology indicated significant morphological changes 25–26 days before laying. Efforts to improve Muscovy production and develop biotechnological techniques to modify these ducks’ reproductive cycle will benefit from these advancements.

Abstract Brood parasitism by cuckoos relies on manipulating hosts to raise their offspring and has evolved stunning adaptations to aid in their deception. The fact that cuckoos usually but not always, remove one or two host eggs while laying their eggs has been a longstanding focus of intensive research. However, the benefit of this behavior remains elusive. Moreover, the recently proposed help delivery hypothesis, predicting that egg removal by cuckoos may decrease the egg‐laying duration in the parasitism process caused by biting action, lacks experimental verification. Therefore, in this study, we examined the effects of egg removal/biting on the egg‐laying speed in the common cuckoo (Cuculus canorus) to experimentally test this hypothesis. We compared the duration of cuckoo egg‐laying in empty nests, nests with host eggs, and nests with artificial blue stick models to test whether cuckoos biting an egg/stick can significantly hasten the egg‐laying speed than no biting action. Our results showed that biting an egg or an object is associated with cuckoos laying approximately 37% faster than when they do not bite an egg or an object. This study provides the first experimental evidence for the help delivery hypothesis and demonstrates that when cuckoos bite eggs or other objects in the nest, they lay eggs more quickly and thereby avoid suffering the hosts' injurious attack.

Within insects, corticotropin-releasing factor/diuretic hormones (CRF/DHs) are responsible for the modulation of a range of physiological and behavioural processes such as feeding, diuresis, and reproduction. Rhopr-CRF/DH plays a key role in feeding and diuresis in Rhodnius prolixus, a blood-gorging insect and a vector for human Chagas disease. Here, we extend our understanding on the role of this neurohormone in reproduction in adult female R. prolixus. Double-label immunohistochemistry displays co-localized staining of CRF-like and the glycoprotein hormone (GPA2/GPB5) subunit GPB5-like immunoreactivity in the same neurosecretory cells (NSCs) in the mesothoracic ganglionic mass (MTGM) and in their neurohemal sites in adult female R. prolixus, suggesting these peptides could work together to regulate physiological processes. qPCR analysis reveals that the transcript for Rhopr-CRF/DH receptor 2 (Rhopr-CRF/DH-R2) is expressed in reproductive tissues and fat body (FB) in adult female R. prolixus, and its expression increases post blood meal (PBM), a stimulus that triggers diuresis and reproduction. Using RNA interference, transcript expression of Rhopr-CRF/DH-R2 was knocked down, and egg production monitored by examining the major yolk protein, vitellogenin (Vg), the number and quality of eggs laid, and their hatching ratio. Injection of dsCRFR2 into adult females reduces Rhopr-CRF/DH-R2 transcript expression, accelerates oogenesis, increases the number of eggs produced, and reduces hatching rate in female R. prolixus. Downregulation of Rhopr-CRF/DH-R2 leads to an increase in the transcript expression of RhoprVg1 in the fat body and ovaries, and increases the transcript level for the Vg receptor, RhoprVgR, in the ovaries. A significant increase in Vg content in the fat body and in the hemolymph is also observed. Incubation of isolated tissues with Rhopr-CRF/DH leads to a significant decrease in transcript expression of RhoprVg1 in the fat body and RhoprVg1 in the ovaries. In addition, Rhopr-CRF/DH reduces transcript expression of the ecdysteroid biosynthetic enzymes and reduces ecdysteroid titer in the culture medium containing isolated ovaries. These results suggest the involvement of the CRF-signaling pathway in reproduction, and that Rhopr-CRF/DH acts as a gonad-inhibiting hormone in the adult female R. prolixus, as previously shown for the colocalized glycoprotein, GPA2/GPB5. [ABSTRACT FROM AUTHOR]

Termite colony foundation precedes the incipient stage, when the first oviposition cycle takes place, followed by months of reproductive inactivity. The royal couple is supposed to cease oviposition during this period, investing energy to care for the first brood. When a suitable number of alloparents differentiate, egg-laying resumes. Here we followed oviposition dynamics, embryo development and queen/king body changes in laboratory colonies of the major pest species Coptotermes gestroi (Rhinotermitidae) and Cryptotermes brevis (Kalotermitidae) during 9 months. We show that they differ in these oviposition dynamics, as C. gestroi queens displayed an uninterrupted oviposition whereas C. brevis laid a cohort of eggs and ceased oviposition during a 3-month period (lag phase). C. gestroi oviposition dynamic was remarkable and suggests that occurrence of progeny was not a limiting factor, thus queens and kings were able to concomitantly invest energy in reproduction and parental care. These findings contrast those reported for rhinotermitids from temperate areas, and we discuss the likely reasons for such a condition, including endogenous rhythms, avoidance of a high mortality rate of the first progeny and adaptation to the weather conditions of the Neotropical region. Oviposition dynamic in C. brevis resembled those of several termite species, in which the royal couple cease reproduction to care for the first brood. Rearing conditions did not influence oviposition dynamics (egg-laying cycle followed by a lag phase), thus our results on the oviposition of C. gestroi and C. brevis correspond to different reproductive strategies post-foundation adopted by these pest species. [ABSTRACT FROM AUTHOR]

Studying how novel phenotypes originate and evolve is fundamental to the field of evolutionary biology as it allows us to understand how organismal diversity is generated and maintained. However, determining the basis of novel phenotypes is challenging as it involves orchestrated changes at multiple biological levels. Here, we aim to overcome this challenge by using a comparative species framework combining behavioral, gene expression, and genomic analyses to understand the evolutionary novel egg-laying substrate-choice behavior of the invasive pest species Drosophila suzukii. First, we used egg-laying behavioral assays to understand the evolution of ripe fruit oviposition preference in D. suzukii compared with closely related species D. subpulchrella and D. biarmipes as well as D. melanogaster. We show that D. subpulchrella and D. biarmipes lay eggs on both ripe and rotten fruits, suggesting that the transition to ripe fruit preference was gradual. Second, using two-choice oviposition assays, we studied how D. suzukii, D. subpulchrella, D. biarmipes, and D. melanogaster differentially process key sensory cues distinguishing ripe from rotten fruit during egg-laying. We found that D. suzukii's preference for ripe fruit is in part mediated through a species-specific preference for stiff substrates. Last, we sequenced and annotated a high-quality genome for D. subpulchrella. Using comparative genomic approaches, we identified candidate genes involved in D. suzukii's ability to seek out and target ripe fruits. Our results provide detail to the stepwise evolution of pest activity in D. suzukii, indicating important cues used by this species when finding a host, and the molecular mechanisms potentially underlying their adaptation to a new ecological niche.

Tetranychus urticae, a prominent pest mite in strawberry and vegetable cultivation in China, has developed escalating resistance due to extensive chemical pesticide application. Consequently, there is an urgent need to identify safe and efficacious methods to reduce resistance development. In this study, 38 commercially available plant essential oils (EOs) were screened for their acaricidal potential and ability to inhibit oviposition. The findings revealed that 13 EOs exhibited notable acaricidal activity, with lemon EO demonstrating the highest toxicity, followed by sage, patchouli, frankincense, lemongrass, palmarosa, and oregano EOs. In addition, 18 EOs displayed significant inhibitory effects on oviposition, with lemon EO exhibiting the highest inhibition rate (99.15%) and inhibition index (0.98). Subsequently, sage, frankincense, clove, lemongrass, oregano, patchouli, myrrh, black pepper, palmarosa, and geranium EOs also showed inhibition rates exceeding 50%. Despite black pepper, clove, myrrh, and oregano EOs demonstrating relatively low toxicity against T. urticae, they exhibited heightened efficacy in inhibiting oviposition and suppressing population expansion. This study conducted a comparative assessment of the acaricidal and oviposition inhibition activities of EOs and their principal constituents, thus providing a theoretical basis for the development of botanical acaricides against T. urticae.

Within insects, corticotropin-releasing factor/diuretic hormones (CRF/DHs) are responsible for the modulation of a range of physiological and behavioural processes such as feeding, diuresis, and reproduction. Rhopr-CRF/DH plays a key role in feeding and diuresis in Rhodnius prolixus, a blood-gorging insect and a vector for human Chagas disease. Here, we extend our understanding on the role of this neurohormone in reproduction in adult female R. prolixus. Double-label immunohistochemistry displays co-localized staining of CRF-like and the glycoprotein hormone (GPA2/GPB5) subunit GPB5-like immunoreactivity in the same neurosecretory cells (NSCs) in the mesothoracic ganglionic mass (MTGM) and in their neurohemal sites in adult female R. prolixus, suggesting these peptides could work together to regulate physiological processes. qPCR analysis reveals that the transcript for Rhopr-CRF/DH receptor 2 (Rhopr-CRF/DH-R2) is expressed in reproductive tissues and fat body (FB) in adult female R. prolixus, and its expression increases post blood meal (PBM), a stimulus that triggers diuresis and reproduction. Using RNA interference, transcript expression of Rhopr-CRF/DH-R2 was knocked down, and egg production monitored by examining the major yolk protein, vitellogenin (Vg), the number and quality of eggs laid, and their hatching ratio. Injection of dsCRFR2 into adult females reduces Rhopr-CRF/DH-R2 transcript expression, accelerates oogenesis, increases the number of eggs produced, and reduces hatching rate in female R. prolixus. Downregulation of Rhopr-CRF/DH-R2 leads to an increase in the transcript expression of RhoprVg1 in the fat body and ovaries, and increases the transcript level for the Vg receptor, RhoprVgR, in the ovaries. A significant increase in Vg content in the fat body and in the hemolymph is also observed. Incubation of isolated tissues with Rhopr-CRF/DH leads to a significant decrease in transcript expression of RhoprVg1 in the fat body and RhoprVg1 in the ovaries. In addition, Rhopr-CRF/DH reduces transcript expression of the ecdysteroid biosynthetic enzymes and reduces ecdysteroid titer in the culture medium containing isolated ovaries. These results suggest the involvement of the CRF-signaling pathway in reproduction, and that Rhopr-CRF/DH acts as a gonad-inhibiting hormone in the adult female R. prolixus, as previously shown for the colocalized glycoprotein, GPA2/GPB5.

Geophagy has been documented in different animal taxa including Aves and particularly in Passeriformes. However, no geophagic activity has been reported in the genus Turdoides of the family Leiothrichidae belonging to the passerine order. Studies reveal the behaviour of geophagy to be aiding in nutrient supplementation, toxin neutralisation, cytoprotection, gut pH stabilisation and parasite liberation. Here, we provide a record of geophagy in Jungle Babbler Turdoides striata in a peri-urban area of Berhampur city in India. Although this species, being insectivorous, was thought to be feeding on insects, nevertheless, close observations confirmed the activity to be a case of geophagy, which was followed up by nest-building, egg-laying and hatching. The soil samples from the geophagic sites (Ca = 2415 mg/kg) contained 130% more Ca than that of the non-geophagic sites (Ca = 1050 mg/kg). The biochemical requirement of calcium throughout the reproductive phase of Turdoides sp. may corroborate the soil consumption instinct, which was also extrapolated from the reproductive success observed, because the demand for calcium in birds remains high during the egg-laying time. Although the possible explanations for geophagy, reported for the first time in this species, were oriented specifically towards Ca supplement, the present findings provide impetus for furthering research in this domain. [ABSTRACT FROM AUTHOR]

The Rio skate Rioraja agassizi is endemic to coastal waters of the Western South Atlantic. The species is common in the coasts of Argentina, Uruguay and Brazil. Previous studies performed in South Brazil, demonstrated that its hatched egg capsules are the most abundant among the co-occurring species. The aim of this study was to assess seasonality in the monthly frequency of egg capsules of R. agassizi at Praia do Cassino (33°07′34″S 52°38′22″W/ 33.126080°S 52.639327°W), southernmost coast of Brazil, over a two-year sampling. The egg capsules were manually collected from the edge of the beach in a belt transect of 1 km long and ca. 0.1 km width, on a weekly basis. After the collections, the capsules were taken to the laboratory for identification at the species level and morphometric measurements. To study the seasonality in the oviposition in R agassizi, data were analyzed monthly, seasonally and annually; accordingly, the data were expressed as non-parametric and heterogeneous, thus, statistical tests were applied to verify trends, significant differences, and descriptive parameters within each scale. In the annual and interannual data, there were statistically significant differences and trends between the sampling periods. Thus, these series of data collected are in fact random and the values demonstrated a randomness in the study site. As for the seasonal data, at least one of the seasons has a significantly different distribution. [ABSTRACT FROM AUTHOR]

The Burdwood Bank (BB) is a subantarctic area, where two of the three Marine Protected Areas (MPA) of the Argentinean Exclusive Economic Zone are located: Namuncurá I, and Namuncurá II. The area is characterized by a high biodiversity of benthic invertebrates and teleost fishes; however, the available information on oviparous chondrichthyans is scarce. The aim of this study is to explore the potential reproductive use that oviparous chondrichthyans could make of the area based on the presence of egg-laying grounds. Additionally, we aim to provide an updated checklist of the species that inhabit the BB. Samples of specimens and egg capsules collected in four research cruises carried out between 2016 and 2018 were analyzed. Six skate species were found in both MPAs: Amblyraja doellojuradoi, Bathyraja albomaculata, B. brachyurops, B. macloviana,B. scaphiops, and Psammobatis rudis; whereas B. cousseauae, and B. magellanica were found exclusively in Namuncurá I, and B. multispinis in Namuncurá II. Here we report, for the first time, the presence of egg-laying grounds for five chondrichthyan species in the BB area: A. doellojuradoi, B. brachyurops, B. macloviana, B. scaphiops, and P. rudis. The results obtained highlighted the importance of the region for the conservation of oviparous chondrichthyans found in the southern Patagonian shelf. [ABSTRACT FROM AUTHOR]

ABSTRACT The aim of this study was to evaluate the reproductive performance of red-winged tinamous in captivity using different mating systems during three breeding seasons. The data were collected from August to March during three breeding seasons of the species. Ten couples and four groups of red-winged tinamous were randomly selected for formation of the monogamous and polygynous mating system, respectively, with egg collection from both systems. The traits evaluated were number of eggs per female, egg breaking and egg fertilization. Data were statistically analyzed by the least square method and logistic regression. Animals in couples mating strategy were superior (P

The article presents the results of predicting the laying capacity of hens of different genotypes during an experiment to study the effectiveness of crossing roosters of imported meat crosses with meat-egg females of domestic selection. The average percentage of deviations of the actual bearing capacity values from the theoretically calculated values was generally low. It amounted to 0.82-4.55 % according to the model of T. Bridges and 0.8-3.28 % according to F. Richards. In the same group of chickens, the last model showed slightly more minor deviations than the model of T. Bridges. The most remarkable correspondence between the actual values of laying and those predicted by both models was determined in F1 chickens of the "K-2" group. Insignificant differences between the actual laying values and those predicted by both models were noted in F10 meat-egg chickens of the original maternal form, their F1 offspring, and chickens of the "K-5" group - 0.82-1.96 % according to the model of T. Bridges, 0.81-0.91 % according to the model of F. Richards. It is possible that the actual laying level of the birds of these groups determined in our research corresponded to the active paratypic factors in their maintenance, which is shown by the applied mathematical models by the high degree of coincidence of the calculated values with the actual ones. In a somewhat specific way, the models predicted laying in hens of other experimental groups. Thus, the model of T. Bridges underestimated the predicted bearing capacity by 3.59-8.25 %. Whereas the model of F. Richards also underestimated egg laying in the 5-7 months by 0.75-3.59 %, and in the last month, on the contrary, overestimated it - by 1.79-4.33 %. Although, in the end, the deviations of the predicted values from the actual values were slight - 2.82-4.55 % according to T. Bridges and 2.15-3.28 % according to F. Richards. The analysis of load-carrying curves calculated according to models showed a significant coincidence of actual and theoretical values - the R2 value, which determined the degree of correspondence between empirical and calculated load-carrying values, was high and amounted to 99.63-99.92 % according to the model of T. Bridges and 99.65-99.98 % according to the function of F. Richards. [ABSTRACT FROM AUTHOR]

The evolution of a placenta requires several steps including changing the timing of reproductive events, facilitating nutrient exchange, and the capacity for maternal–fetal communication. To understand the evolution of maternal–fetal communication, we used ligand-receptor gene expression as a proxy for the potential for cross-talk in a live-bearing lizard (Pseudemoia entrecasteauxii) and homologous tissues in a related egg-laying lizard (Lampropholis guichenoti). Approximately 70% of expressed ligand/receptor genes were shared by both species. Gene ontology (GO) analysis showed that there was no GO-enrichment in the fetal membranes of the egg-laying species, but live-bearing fetal tissues were significantly enriched for 50 GO-terms. Differences in enrichment suggest that the evolution of viviparity involved reinforcing specific signalling pathways, perhaps to support fetal control of placentation. One identified change was in transforming growth factor beta signalling. Using immunohistochemistry, we show the production of the signalling molecule inhibin beta B (INHBB) occurs in viviparous fetal membranes but was absent in closely related egg-laying tissues, suggesting that the evolution of viviparity may have involved changes to signalling via this pathway. We argue that maternal–fetal signalling evolved through co-opting expressed signalling molecules and recruiting new signalling molecules to support the complex developmental changes required to support a fetus in utero. This article is part of the theme issue 'Extraembryonic tissues: exploring concepts, definitions and functions across the animal kingdom'. [ABSTRACT FROM AUTHOR]

Abstract Several studies have described the effects of human tumor necrosis factor alpha (hTNF-α) on Schistosoma mansoni. hTNF-α affects the worm’s development, metabolism, egg-laying, gene expression and protein phosphorylation. The available data on the influence of hTNF-α on egg-laying in S. mansoni are controversial, but understanding the mechanism of egg-laying regulation in this species is essential in combating schistosomiasis. We characterized the effects of in vitro treatment of S. mansoni adult worms with different doses of hTNF-α (5, 20 and 40 ng/ml) for 5 days. We explored the effects on egg-laying rate, glucose levels, ATP metabolism, and messenger RNA (mRNA) expression levels of lactate dehydrogenase, glucose transporters and the parasite gene which acts as an hTNF-α receptor, SmTNFR. hTNF-α influenced egg-laying in a time- and dose-dependent manner: at a dose of 40 ng/ml, egg-laying increased on day 2 and decreased on days 3 and 4; at 20 ng/ml, egg-laying decreased on day 3; while at 5 ng/ml, egg-laying decreased on day 4. The total number of eggs produced was not affected by the different treatments, but the egg-laying dynamics were: the median egg-laying time decreased significantly with treatment, and egg developmental stages and size were also affected. At 5 and 20 ng/ml hTNF-α, lactate production diminished on day 3 up to day 5, while glucose uptake increased on day 5. At 40 ng/ml, glucose uptake diminished on day 1 up to day 3, while ATP accumulation was detected on day 5. No significant changes in mRNA expression were detected in any of the treatments. We found that crosstalk involving hTNF-α and parasite signaling plays a role in the fine-scale regulation of the worm’s metabolism and physiology, and points to new strategies for disease control. Graphical abstract

• CAPA-2-like and GPB5-like immunoreactivity is colocalized in cells in the MTGM. • CAPAR downregulation decreases vitellogenin levels in the fat body and hemolymph. • CAPAR downregulation decreases egg production and reduces hatching rate. • RhoprCAPA-2 acts directly on the fat body to increase vitellogenin production. • RhoprCAPA-2 acts as a gonadotropin in adult female R. prolixus. CAPA peptides play diverse roles in insects, modulating muscle contraction, regulating fluid balance, and reproduction. In Rhodnius prolixus , a hematophagous insect and a vector for human Chagas disease, three CAPA peptides are encoded by the capability gene , including RhoprCAPA-1, RhoprCAPA-2, and RhoprCAPA-PK-1. RhoprCAPA-2 is an anti-diuretic hormone in R. prolixus. Here, we explore the involvement of RhoprCAPA-2 in reproduction in adult female R. prolixus. Double-label immunohistochemistry reveals co-localization of RhoprCAPA-2-like and the glycoprotein hormone (GPA2/GPB5) subunit GPB5-like immunoreactivity in neurosecretory cells in the mesothoracic ganglionic mass and in their neurohemal sites, suggesting these peptides can be co-released to regulate physiological processes. qPCR analysis reveals changes in transcript expression levels of the RhoprCAPA receptor (CAPAR) in the fat body and reproductive tissues after feeding in adult female R. prolixus. RNA interference-mediated knockdown of CAPAR transcript decreases egg production and reduces hatching rate and survival rate in female R. prolixus. Downregulation of CAPAR decreases vitellogenin RhoprVg1 transcript expression in the fat body and deceases its receptor RhoprVgR transcript level in the ovaries; accompanied by a reduction in vitellogenin content in the fat body and hemolymph. Incubation of fat body and ovaries in vitro with RhoprCAPA-2 increases RhoprVg1 transcript expression in the fat body, vitellogenin content in the fat body culture medium, and increases RhoprVgR transcript in the ovaries. These findings implicate the CAPA signaling pathway in reproduction, with RhoprCAPA-2 acting as a gonadotropin in adult female R. prolixus. [ABSTRACT FROM AUTHOR]

Insect colonization of continental aquatic ecosystems and their immediate surroundings was paramount for the establishment of complex trophic nets and organic‐matter recycling in those environments. True flies and other insects such as mayflies developed crucial ecological roles in early continental aquatic ecosystems, as early as the Triassic. However, the mode and tempo of these processes remain poorly known, partly due to a critical fossil record gap before the Middle Triassic. Here we study the dipterans from the early Middle Triassic Konservat‐Lagerstätte of Pedra Alta (Aegean, early Anisian, Spain), which yields the oldest records of the order. Protoanisolarva juarezi gen. et sp. nov., based on an exceptionally preserved larva, shares key features with the extant nematoceran family Anisopodidae. Developing in inferred moist terrestrial environments contiguous with pools inhabited by aquatic organisms, it represents the only known Triassic dipteran larva with terrestrial affinities indicating that the amphipneustic respiratory system of insect larvae extends back to c. 247 Ma. Two nematoceran aquatic pupae are also described: one classified as Voltziapupa cf. cornuta, and the other as an indeterminate taxon. Finally, an egg cluster belonging to the ootaxon Clavapartus latus is likely to have been produced by chironomids. These eggs were included in a mucilaginous matrix, a probable adaptation against predation and/or changing conditions, including desiccation. These new findings provide key data on the early evolutionary history of the mega‐diverse order Diptera, the ecology of their ancestral pre‐adult forms, and the functioning of early Middle Triassic continental aquatic ecosystems. [ABSTRACT FROM AUTHOR]

The size of organisms may result from various, sometimes antagonistic forces operating on distinct traits, within an evolutionary framework that may also be constraining. Morphological allometry, referring to the way trait size scales with body size, has been shown to reflect ecological adaptation to the mean size of the resource exploited. We examined the allometric relationships between rostrum and body size among four insect (Curculio spp.) specialists of oak acorns. In all four species, weevil females drill a hole with their rostrum prior depositing one or a few eggs inside the seed. The four weevil species, that coexist on the same individual trees, displayed partitioned egg-laying periods in the year, thereby encountering acorns of different size and maturation stage. We found marked differences in the allometric slope among females: species laying eggs late in the season had a steeper slope, leading to increasingly longer rostrum relative to body length, along with the mean size of the growing acorns. Females of the smallest species had the longest oviposition period and also had the steepest slope, which provided them with the most variable rostrum length, thereby matching the variable size of the resource through time. Our work highlights the need to consider not only the average size but also the degree of variability in resource size to understand the adaptive value of allometric relationships. [ABSTRACT FROM AUTHOR]

Micro-elements are essential for the optimal feeding of broiler hens. Since the chelated micro-elements negatively affect the content of micro- and macro-minerals, there has been a tendency to apply them as an alternative to common mineral forms of micro-elements in poultry diets. This paper reviews the effects of chelates of micro-elements (iron, copper, zinc, manganese, and selenium) on broiler breeder hens’ internal and external egg quality and their egg products. The use of chelated micro-elements compared to the mineral forms does not have a significant effect on the performance of broiler breeder flocks, but they have significantly positive effects on the internal and external egg quality of broiler breeder flocks. The chelated micro-elements were also better than mineral resources of micro-elements in improving fertility (0.59%), hatchability (0.81%), and reducing mortality of progeny (2.25%). Chelated micro-elements have no negative impact on blood biochemistry or the immune system of broiler breeder hens and decrease cholesterol (0.84 mmol/l) and triglycerides (0.04 mmol/l) in most cases in comparison with the other mineral forms. Therefore, chelated forms of micro-elements instead of the inorganic mineral forms in diets of broiler breeder hens provide better protection for birds and the environment and also improve egg quality. [ABSTRACT FROM AUTHOR]

The minimum required level of egg cross-laying area has been determined for keeping hens in multi-tier cage batteries. The research was conducted in the conditions of the modern industrial complex of Ukraine on production of food eggs on laying hens of 3 groups of cross ”Hy-Line W-36”, created in the USA. Each group of hens was kept in a separate poultry house with an area of 2640 m² (110 × 24 m, h = 13.5 m), equipped with 12-tier cage batteries (”Salmet”, Germany). The batteries consisted of 18,144 cages with an area of 7506 cm² (120.00 × 62.55 cm). Hens of the 1st group were placed 18 birds in each cage, the 2nd – 19, in the 3rd – 20. Therefore, their initial number in the 1st group was 326592 hens, in the 2nd – 344736 hens, in the 3rd – 362880 hens, or 18144 and 36288 hens more. The provision of hens with the area was 417,395 and 375 cm²/bird. In the 1st group it met the normative requirements in Ukraine (400–450 cm²/bird), and in the experimental ones (2 and 3 gr.) – it was slightly lower. The experiment lasted 44 weeks, namely until the laying hens reached 62 weeks of age. Hens of 1st and 2nd groups surpassed their counterparts of 3rd group (239.8 eggs, p < 0.05), in terms of the number of eggs obtained per initial laying hen at 62 weeks of age (249.4 eggs). They surpassed them in the level of preservation (93.4–94.2% and 85.4%). 31837 eggs were received from laying hens of 1st group from 1 m² of the area of a poultry house for the period of experiment, from the 2nd group – 32918 eggs, from the 3rd group – 32832 eggs. Egg mass was obtained from 1 m² area: 1st group – 2002.6 kg, 2nd group – 2073.8 kg and 3rd group – 2071.7 kg. The efficiency of egg production in 1st group was 21.2 c.u., in the 2nd – 21.5 c.u., in the 3rd – 20.5 c.u. The conclusion was made about the possibility of making adjustments to the regulations governing the provision of the area of laying hens of egg-laying crosses. In particular, the lower limit of security should be set at 395 cm²/birds for their content in 12-tier cage batteries. It has been suggested that the excess of the reference values of aspartateaminotransferase and lactatedehydrogenase activity in the blood of hens is associated with a decrease in their safety and productivity, which is due to insufficient provision of their space for multi-tier cage batteries. [ABSTRACT FROM AUTHOR]

Assays of behavior in model organisms play an important role in genetic screens, drug testing, and the elucidation of gene-behavior relationships. We have developed an automated, high-throughput imaging and analysis method for assaying behaviors of the nematode C. elegans. We use high-resolution optical imaging to longitudinally record the behaviors of 96 animals at a time in multi-well plates, and computer vision software to quantify the animals' locomotor activity, behavioral states, and egg laying events. To demonstrate the capabilities of our system we used it to examine the role of serotonin in C. elegans behavior. We found that egg-laying events are preceded by a period of reduced locomotion, and that this decline in movement requires serotonin signaling. In addition, we identified novel roles of serotonin receptors SER-1 and SER-7 in regulating the effects of serotonin on egg laying across roaming, dwelling, and quiescent locomotor states. Our system will be useful for performing genetic or chemical screens for modulators of behavior., (© The Author(s) 2024. Published by Oxford University Press on behalf of The Genetics Society of America. All rights reserved. For commercial re-use, please contact reprints@oup.com for reprints and translation rights for reprints. All other permissions can be obtained through our RightsLink service via the Permissions link on the article page on our site—for further information please contact journals.permissions@oup.com.)

Abstract Background Allatotropin, a neuropeptide found in several invertebrates indirectly regulates vitellogenesis by stimulating juvenile hormone biosynthesis by the corpora allata. Here, we cloned and expressed the gene encoding allatotropin of Spodoptera litura (tobacco cutworm), a polyphagous pest in the Asian tropics. This study is aimed at studying the effect of recombinant protein on egg-laying in females of S. litura as it could be used as a method to control the pests from a reproductive perspective. Results The protein encodes a full-length open reading frame consisting of 173 amino acids and was rich in arginine (10%) and glutamic acid (9.3%). The theoretical pI of the protein was 5.47 and a hydrophobic signal peptide of 22 residues was predicted. The recombinant allatotropin was expressed in Escherichia coli BL21 (DE3) and purified by nickel exchange chromatography. The molecular weight of the recombinant protein was about 37 kDa and expression levels up to 5.3 mg/ml were achieved. Injection assay in vitro indicated that allatotropin induces egg-laying during the first scotophase after treatment in females of Spodoptera litura. Conclusion Allatotropin induces egg-laying in female moths and could be a potential molecule for the development of control strategies against Spodoptera litura. In this strategy, the protein if delivered to the females before mating may lead to accelerated egg deposition much before she encounters the male moths, thus the population being checked as the eggs deposited by the females are unfertilized. Thus, the present work could lead to the development of a protein based biopesticide resulting into a species-specific and an eco-friendly way of pest control.

Abstract Background The host specificity and host range of the dry bean beetle, Acanthoscelides obtectus (Coleoptera: Chrysomelidae, Bruchinae), a seed predator of beans, is poorly known. In addition, the female oviposition preference and larval performance relationship is complicated by the respective importance of seed coat and cotyledon, because, paradoxically, females lay eggs on the basis of stimuli of the seed coat alone, without directly being able to assess the quality of the cotyledon’s suitability for larval development. Conversely, the thickness of seed coat may prevent first instar larvae from entering the seeds, even if cotyledons are suitable for development. Methods The seeds of 62 leguminous species and 75 cultivars and accessions occurring in Hungary were evaluated for preference-performance relations. The preference of female bean beetles for seeds was measured in no-choice egg-laying tests. The ability of first instar larvae to overcome the seed coat as a physical barrier was tested with intact seed coat, while pre-drilled seed coats allowed the larvae to assess the suitability of cotyledon for development. The number of emerging adults was recorded. The thickness of seed coats and the weight of seeds were measured. Nonparametric tests and logistic regression were used for the statistical analyses of data and effect sizes were also calculated. Results Seeds of 18 leguminous species (35% of them Lathyrus) supported larval development to adults if the seed coat was pre-drilled; however, only nine leguminous species supported development to adults if the seed coat was intact. Seed coat thickness beyond a critical threshold of 0.1 mm strongly influenced survival of first instar larvae. There was no overall positive correlation between oviposition preference and larval performance, except for 16 so-called acceptable non-hosts (Kendall’s τ = 0.3088). A. obtectus females also showed an ovipositional hierarchy of legume species even in no-choice tests. Conclusions The results suggest that whereas the use of some acceptable non-host species by the A. obtectus is possible in seed stores, the same is unlikely under outdoor conditions, where the recognition of a diverse set of seed pod-related compounds would be necessary to induce egg-laying.

ABSTRACT: The impact of varying light intensities on layer pullets is not yet well understood. Behaviorally, brighter illumination may increase pullet activity levels by allowing better navigation in the complexity of non-cage systems. In addition, light intensity was previously demonstrated to affect the levels of calcium and phosphate regulating hormones in mice. The objective of this study was to examine how exposure of pullets to different light intensity affects their calcium and phosphorus homeostasis. Lohmann LSL-Lite and Lohmann Brown-Lite pullets were randomized into 4 individually controlled rooms with 6 pens per room, which were assigned to 10 or 50 lux light intensity supplied via white LED lighting during the photophase. After 8 and 16 wk of exposure, plasma calcium, phosphorus, and magnesium were measured by inductively coupled plasma optical emission spectrometry; and parathyroid hormone, 1,25-dihydroxyvitamin D, fibroblast growth factor 23, and markers of bone formation and resorption were measured by ELISA. Intestine and kidney samples were collected at 16 wk and gene expression of receptors for calcium and phosphate regulating hormones was assessed. The data were analyzed by one-way ANOVA. Lohmann Brown-Lite pullets exposed to 50 lux for 8 wk exhibited lower ionized Ca levels and a trend for increased bone formation markers compared to pullets reared in 10 lux. Thus, higher light intensity during rearing may beneficially affect calcium homeostasis and bone formation in young Lohmann Brown-Lite chicken.

The cuttlefish (Sepia officinalis) is a Cephalopod mollusk that lives in the English Channel and breeds in coastal spawning grounds in spring. A previous work showed that the control of egg-laying is monitored by different types of regulators, among which neuropeptides play a major role. They are involved in the integration of environmental cues, and participate in the transport of oocytes in the genital tract and in the secretion of capsular products. This study addresses a family of neuropeptides recently identified and suspected to be involved in the control of the reproduction processes. Detected by mass spectrometry and immunocytochemistry in the nerve endings of the accessory sex glands of the females and ovary, these neuropeptides are also identified in the hemolymph of egg-laying females demonstrating that they also have a hormone-like role. Released in the hemolymph by the sub-esophageal mass, a region that innervates the genital tract and the neurohemal area of the vena cava, in in vitro conditions these neuropeptides modulated oocyte transport and capsular secretion. Finally, in silico analyses indicated that these neuropeptides, initially called FLGamide, had extensive structural homology with orcokinin B, which motivated their name change. [ABSTRACT FROM AUTHOR]

A schoenobiine species, Scirpophaga tripunctalis sp. nov. is described from Central Honshu, Japan. Some morphological features of this new species are revised based on the terminology previously used in the genus Scirpophaga. The DNA barcode of the species is given and compared with the known barcodes of the other related schoenobiine species, including S. incertulas. Egg-laying habit and the morphology of the 1st instar larva are briefly described. The habitat of the new species is discussed referencing those of other Scirpophaga species. [ABSTRACT FROM AUTHOR]

Cave animals are biological models of fast evolutionary change induced by transition to extreme subterranean environments. But their concealed lifestyle makes it inherently difficult to study life-history changes. Therefore, currently very little is known on the reproduction of cave species, and even less is known on general patterns and potentially shared reproductive strategies. Theory predicts that the cave environment favours the production of a few well-developed offspring and live birth. For one of the most enigmatic cave animals, the olm (Proteus anguinus), it has been debated fiercely whether they reproduce by live birth (viviparity), egg-laying (oviparity) or facultatively. While successes in captive breeding after the 1950s report oviparity as the single parity mode, some historically older observations claimed viviparity. The controversial neo-Lamarckist Paul Kammerer even claimed to have induced changes in parity mode by altering environmental conditions. Here, we report on the feeding and regurgitation of fire salamander (Salamandra salamandra) larvae by olms. The salamander larvae showed clear teeth marks and other injuries on the head caused by the olm, yet one larva was still alive after regurgitation. We suggest that historical reports of olm viviparity could have been misled by regurgitated salamander larvae. Our data bring additional indications that at least some of Kammerer's experiments were fraudulent. [ABSTRACT FROM AUTHOR]

The transient receptor potential-like channel (TRPL) is a member of the transient receptor potential (TRP) channel family involved in regulating many fundamental senses, such as vision, pain, taste, and touch, in both invertebrates and vertebrates. Yet, the function of TRPL in other important biological processes remains unclear. We discover that TRPL regulates egg laying in two insect species, the brown planthopper, Nilaparvata lugens, and the fruit fly, Drosophila melanogaster. In both insects, trpl is expressed in the female reproductive organ. Loss of trpl leads to significantly defects in egg laying. In addition, TRPL is functionally interchangeable between the brown planthoppers and flies in egg laying. Altogether, our work uncovers a novel role played by TRPL in regulating egg laying and indicates TRPL as a potential pesticide target in brown planthoppers. [ABSTRACT FROM AUTHOR]

The knowledge of oviposition preference by female insects is a basic requirement for developing insect pest scouting methods to determine the potential damage and to apply control measures for key pest like Earias vittella in cotton. Field experiments were conducted to assess the distribution of E. vittella eggs within the cotton plant. Out of 240 plants inspected, E. vittella females laid 204 and 194 eggs on 40.9% and 36.9%of the plants in 2011 and 2012, respectively. Spearman Rank Correlation showed that a significant and positive relationship (association) existed between the number of infested plants or plant parts and number of eggs laid. In every week, an average of 6.1±1.2 plants were infested with13.6±2.7 eggs in 2011 and 5.5±1.1 plants with 12.9±2.2 eggs in 2012. Four and three peak egg-laying periods were observed in 2011 and 2012, respectively. Taylor's power law of regression showed an aggregate spatial pattern distribution of eggs for E. vittella in plants in both years. Variance-to-mean ratio, the chi-square test index, and Lloyd index of patchiness indicated uniform eggs distribution for both years. Within the plants, the most preferred oviposition sites were just below the terminal portion on such structures as the leaves, terminal buds and NE leaves. The current study regarding the site selection for oviposition provides information that can be used to develop guidelines for E. vittella management in cotton production. [ABSTRACT FROM AUTHOR]

Egg production is the most important trait of laying hens. To identify molecular markers and candidate genes associated with egg production and quality, such as body weight at first oviposition (BWF), the number of eggs produced in 500 days (EN500), egg weight (EW), egg shell thickness (EST), egg shell strength (ESS), and Haugh unit (HU), a genome-wide analysis was performed in 266 LingKun Chickens. The results showed that thirty-seven single nucleotide polymorphisms (SNPs) were associated with all traits (p < 9.47 × 10−8, Bonferroni correction). These SNPs were located in close proximity to or within the sequence of the thirteen candidate genes, such as Galanin And GMAP Prepropeptide (GAL), Centromere Protein (CENPF), Glypican 2 (GPC2), Phosphatidylethanolamine N-Methyltransferase (PEMT), Transcription Factor AP-2 Delta (TFAP2D), and Carboxypeptidase Q (CPQ) gene related to egg-laying and Solute Carrier Family 5 Member 7 (SLC5A7), Neurocalcin Delta (NCALD), Proteasome 20S Subunit Beta 2 (PSMB2), Slit Guidance Ligand 3 (SLIT3), and Tubulin Tyrosine Ligase Like 7 (TTLL7) genes related to egg quality. Interestingly, one of the genes involved in bone formation (SLIT3) was identified as a candidate gene for ESS. Our candidate genes and SNPs associated with egg-laying traits were significant for molecular breeding of egg-laying traits and egg quality in LingKun chickens.

Several studies have described the effects of human tumor necrosis factor alpha (hTNF-α) on Schistosoma mansoni. hTNF-α affects the worm's development, metabolism, egg-laying, gene expression and protein phosphorylation. The available data on the influence of hTNF-α on egg-laying in S. mansoni are controversial, but understanding the mechanism of egg-laying regulation in this species is essential in combating schistosomiasis. We characterized the effects of in vitro treatment of S. mansoni adult worms with different doses of hTNF-α (5, 20 and 40 ng/ml) for 5 days. We explored the effects on egg-laying rate, glucose levels, ATP metabolism, and messenger RNA (mRNA) expression levels of lactate dehydrogenase, glucose transporters and the parasite gene which acts as an hTNF-α receptor, SmTNFR. hTNF-α influenced egg-laying in a time- and dose-dependent manner: at a dose of 40 ng/ml, egg-laying increased on day 2 and decreased on days 3 and 4; at 20 ng/ml, egg-laying decreased on day 3; while at 5 ng/ml, egg-laying decreased on day 4. The total number of eggs produced was not affected by the different treatments, but the egg-laying dynamics were: the median egg-laying time decreased significantly with treatment, and egg developmental stages and size were also affected. At 5 and 20 ng/ml hTNF-α, lactate production diminished on day 3 up to day 5, while glucose uptake increased on day 5. At 40 ng/ml, glucose uptake diminished on day 1 up to day 3, while ATP accumulation was detected on day 5. No significant changes in mRNA expression were detected in any of the treatments. We found that crosstalk involving hTNF-α and parasite signaling plays a role in the fine-scale regulation of the worm's metabolism and physiology, and points to new strategies for disease control. [ABSTRACT FROM AUTHOR]

Helminth infections continue to be a neglected global threat in tropical regions, and there have been growing cases of anthelmintic resistance reported towards the existing anthelmintic drugs. Thus, the search for a novel anthelmintic agent has been increasing, especially those derived from plants. Leucaena leucocephala (LL) is a leguminous plant that is known to have several pharmacological activities, including anthelmintic activity. It is widely known to contain a toxic compound called mimosine, which we believed could be a potential lead candidate that could exert a potent anthelmintic effect. Hence, this study aimed to validate the presence of mimosine in LL extract and to investigate the anthelmintic effect of LL extract and mimosine on head thrashing, egg-laying, and pharyngeal pumping activities using the animal model Caenorhabditis elegans (C. elegans). Mimosine content in LL extract was confirmed through an HPLC analysis of spiking LL extract with different mimosine concentrations, whereby an increasing trend in peak heights was observed at a retention time of 0.9 min. LL extract and mimosine caused a significant dose-dependent increase in the percentage of worm mortality, which produced LC50s of 73 mg/mL and 6.39 mg/mL, respectively. Exposure of C. elegans to different concentrations of LL extract and mimosine significantly decreased the head thrashing, egg-laying, and mean pump amplitude of pharyngeal pumping activity. We speculated that these behavioral changes are due to the inhibitory effect of LL extract and mimosine on an L-type calcium channel called EGL-19. Our findings provide evidential support for the potential of LL extract and its active compound, mimosine, as novel anthelmintic candidates. However, the underlying mechanism of the anthelmintic action has yet to be elucidated. [ABSTRACT FROM AUTHOR]

What physiological and neuro-molecular changes control the female oviposition behavior post-mating in insects? The molecular changes that occur in a gravid female insect are difficult to dissect out considering the distinct behavioral patterns displayed by different insect groups. To understand the role of the brain center in Oriental fruit fly, Bactrocera dorsalis oviposition, egg-laying behavior was analyzed in γ-octalactone exposed, decapitated mated B. dorsalis females. Interestingly, the females displayed a possible urge to oviposit, which suggests a natural instinct to pass on the gene pool. Expression analysis of certain genes involved in oviposition behavior was also carried out in these insects to explore the molecular aspects of such behavior. This study tries to assess the involvement of brain center in egg-laying and also explore the role of certain neurotransmitter-related receptors in decapitated B. dorsalis oviposition behavior. Our results indicate that B. dorsalis oviposition behavior could potentially have a bypass route of neuronal control devoid of the brain. The study reported here establishes that decapitation in gravid females fails to abolish their ability to sense ovipositional cues and also to oviposit. [ABSTRACT FROM AUTHOR]

Background: Elevated temperatures reduce fertilization and egg-laying rates in the octopus species. However, the molecular mechanisms that control the onset of fertilization and egg-laying in the octopus' oviducal gland are still unclear; and the effect of temperature on the expression of key reproductive genes is unknown. This study aims to better understand the molecular bases of octopus fertilization and egg-laying, and how they are affected by elevated temperatures. Method: RNA-seq of oviducal glands was performed for samples before, during, and after fertilization and their transcriptomic profiles were compared. Also, at the fertilization stage, the optimal and thermal-stress conditions were contrasted. Expression levels of key reproductive genes were validated via RT-qPCR. Results: In mated females before egg-laying, genes required for the synthesis of spermine, spermidine, which may prevent premature fertilization, and the myomodulin neuropeptide were upregulated. Among the genes with higher expression at the fertilization stage, we found those encoding the receptors of serotonin, dopamine, and progesterone; genes involved in the assembly and motility of the sperm flagellum; genes that participate in the interaction between male and female gametes; and genes associated with the synthesis of eggshell mucoproteins. At temperatures above the optimal range for reproduction, mated females reduced the fertilization rate. This response coincided with the upregulation of myomodulin and APGW-amide neuropeptides. Also, genes associated with fertilization like LGALS3, VWC2, and Pcsk1 were downregulated at elevated temperatures. Similarly, in senescent females, genes involved in fertilization were downregulated but those involved in the metabolism of steroid hormones like SRD5A1 were highly expressed. [ABSTRACT FROM AUTHOR]