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Desert ecosystems are currently threatened by human activities resulting in the rapid decline of xerophytic plants and specialized fauna. In South America, the demise of cactus species already resulted in the population decline of > 30% of the iconic giant columnar cactus Trichocereus terscheckii. The increasing vulnerability of these keystone species could trigger a cascade of secondary extinctions in highly dependent organisms. Thus, necrotic cacti constitute an important habitat for desert arthropods, yet little is known on the hidden diversity of this neglected niche. We used DNA barcode techniques to survey the diversity of arthropods in a threatened cactus forest dominated by T. terscheckii in northwestern Argentina. We obtained a total of 542 mitochondrial barcode sequences, resulting in 323 Molecular Taxonomic Units (MOTUs) associated to the xerophytic forest and 21 MOTUs exclusive to the giant cactus necrosis. Our results indicated that the area is a biodiversity hotspot within the harsh Andean desert and suggests that nearly 30 species could occur in the decaying cactus, representing the highest richness of cactophilic arthropods recorded in any cactus on the continent to date (6 orders and 16 families). The community structure of cactophilic arthropods showed a phylogenetic clustering pattern, suggesting the coexistence of closely related species. Overall, our study indicates that the giant cactus necrosis sustains a particular phylogenetic diversity of desert arthropods, while demonstrating the efficacy of DNA barcodes for biodiversity assessments in complex and poorly understood ecological systems. [ABSTRACT FROM AUTHOR]

Plant resistance is a key strategy for the management of Oryzophagus oryzae (Costa Lima) (Coleoptera: Curculionidae), an important pest in South American rice paddies. The present study investigated the resistance of rice cultivars in terms of feeding and oviposition preference, growth, development, and biological performance of O. oryzae under natural conditions of field infestation during two consecutive rice seasons. There were no effects of the six cultivars on the feeding and oviposition preferences of O. oryzae as evaluated 5, 8, and 11 d After Flooding (DAF) of the plots, indicating the absence of antixenosis. Cultivars did not differ in terms of egg viability and larval density of first instars on the roots at 15 DAF. Significant differences were found 25 and 35 DAF when larval density per sample was high on 'BRS Pampa CL' (up to 24.5), intermediate on 'BRS Querência' and 'BRS Ligeirinho' (up to 16.1), and low on 'BRS Atalanta', 'BRS Firmeza', and 'Dawn' (up to 8.8). The cultivars 'BRS Atalanta', 'BRS Firmeza', and 'Dawn' caused malnutrition and inhibition of larval growth. These effects, typical of antibiosis, resulted in delayed pupation and emergence of adults; in addition, emerged females had body weight decreased strongly. The cultivars BRS Pampa CL, BRS Querência, and BRS Ligeirinho are susceptible, resulting in high larval populations and more suitable development of O. oryzae; antibiosis, as indicated for 'BRS Atalanta', 'BRS Firmeza', and 'Dawn', probably is the key mechanism of rice resistance to O. oryzae. Graphical Abstract [ABSTRACT FROM AUTHOR]

The genus Eois Hübner (Geometridae: Larentiinae) comprises 254 valid species, 217 of which were described from the Neotropics and 31 of those having their type locality in Brazil. Since this species rich genus has never been revised, and may potentially include many cryptic undescribed species, Eois embodies a problematic taxonomic scenario. The actual diversity of Eois is greatly underestimated and the Brazilian fauna is poorly known, both because of inadequate sampling and because of the potential existence of cryptic species "hidden" within some nominal taxa. In this study we investigated the diversity within a cryptic species complexes associated to the E. pallidicosta and E. odatis clades. We describe three new species Eois oya Moraes & Montebello sp. nov., Eois ewa Moraes & Stanton sp. nov., and Eois oxum Moraes & Freitas sp. nov., in an integrative taxonomy approach, using morphology, host plant use and species delimitation tools. [ABSTRACT FROM AUTHOR]

Insect species richness is estimated to exceed three million species, of which roughly half is herbivorous. Despite the vast number of species and varied life histories, the proportion of herbivorous species among plant-consuming organisms is lower than it could be due to constraints that impose limits to their diversification. These include ecological factors, such as vague interspecific competition; anatomical and physiological limits, such as neural limits and inability of handling a wide range of plant allelochemicals; phylogenetic constraints, like niche conservatism; and most importantly, a low level of concerted genetic variation necessary to a phyletic conversion. It is suggested that diversification ultimately depends on what we call the intrinsic trend of diversification of the insect genome. In support of the above, we survey the major types of host-specificity, the mechanisms and constraints of host specialization, possible pathways of speciation, and hypotheses concerning insect diversification. [ABSTRACT FROM AUTHOR]

Long-term studies (2012-2018) of the formation of the Rhopalosiphum padi (L.) heteroecious population (number of remigrants, oviparae and eggs in autumn, number of perished eggs, fundatrices larvae, timing of flight of emigrants in spring) on the two samples of primary host Padus avium Mill. and P. avium x P. virginiana (L.) characterized by various morpho-physiological features have been carried out. By the methods of mathematical statistics, it has been proved that this formation occurs under the significant influence of the year conditions (A), host plant characteristics (B) and these factors interaction (AB). The most visible was their highly significant impact on the number of wintering aphid eggs (A = 200.42; B = 142.6; AB = 25.612). Plant characteristics such as significantly larger leaf area from the middle part of the shoot on P. avium x P. virginiana, than on P. avium (t = 8.37; p0.01 = 2.85) was important for attracting remigrants and the prone buds on P. avium x P. virginiana - for oviposition and survival of eggs. Correlation between the period of leaf fall and number of aphid eggs on both bird-cherry samples is presented. The effect of weather conditions on R. padi and primary hosts relationships is discussed. Correlation (r = 0.76; p = 0.0048) between average temperature of October and eggs number on P. avium is given. R. fundatrices. [ABSTRACT FROM AUTHOR]

Copyright of Ecologia Mediterranea is the property of Ecologia Mediterranea and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Climate change is expected to have significant and complex impacts on ecological communities. In addition to direct effects of climate on species, there can also be indirect effects through an intermediary species, such as in host–plant interactions. Indirect effects are expected to be more pronounced in alpine environments because these ecosystems are sensitive to temperature changes and there are limited areas for migration of both species (i.e. closed systems), and because of simpler trophic interactions. We tested the hypothesis that climate change will reduce the range of an alpine butterfly (Parnassius smintheus) because of indirect effects through its host plant (Sedum sp.). To test for direct and indirect effects, we used the simulations of climate change to assess the distribution of P. smintheus with and without Sedum sp. We also compared the projected ranges of P. smintheus to four other butterfly species that are found in the alpine, but that are generalists feeding on many plant genera. We found that P. smintheus gained distributional area in climate‐only models, but these gains were significantly reduced with the inclusion of Sedum sp. and in dry‐climate scenarios which resulted in a reduction in net area. When compared to the more generalist butterfly species, P. smintheus exhibited the largest loss in suitable habitat. Our findings support the importance of including indirect effects in modelling species distributions in response to climate change. We highlight the potentially large and still neglected impacts climate change can have on the trophic structure of communities, which can lead to significant losses of biodiversity. In the future, communities will continue to favour species that are generalists as climate change induces asynchronies in the migration of species. [ABSTRACT FROM AUTHOR]

We examine the genetics, morphology and ecology of the widely distributed Megachile concinna species complex (Hymenoptera: Megachilidae), which is composed of numerous taxa of unclear taxonomic status in Africa and the Palearctic. In the Western Palearctic, three genetically distinct operational taxonomic units (OTUs) are found around the Mediterranean Sea: the western Mediterranean OTU M. pusilla, the eastern Mediterranean OTU M. anatolica and the predominantly Arabian OTU M. leucostoma. A morphological cline is present between anatolica and leucostoma in the Near East, despite a lack of mitochondrial introgression between the two; one nuclear marker suggests some gene flow between these OTUs. The contact zone between pusilla and leucostoma could not be sampled but phenotypic intergradation is also observed between these OTUs in northern Africa. In contrast, study of the contact zone between pusilla and anatolica indicates that both OTUs retain phenotypic and genomic integrity in sympatry over a contact zone spanning 1000 km. The arrangement of these three OTUs suggests a ring of interconnected populations around the Mediterranean Sea and sympatry between pusilla and anatolica at both ends of the ring in southeastern Europe. The latter two OTUs exhibit ecological differences, including phenology and host-plant preferences, which may contribute to their isolation. In addition, our results suggest that two OTUs, M. venusta and M. concinna, maintain genetic and phenotypic integrity in sympatry in parts of Africa; the latter is recognized as a valid species here. Lastly, our results indicate that two OTUs have been introduced independently into the New World, pusilla in North America and Argentina, and concinna in the Antilles. [ABSTRACT FROM AUTHOR]

The introduced beetle Ophraella communa was first found in 1996 in Japan and has rapidly expanded its distribution to include regions that encompass a wide range of latitude and altitude and are dominated by different host-plants. In this study, we investigated geographic variation in its photoperiodic response for the induction of reproductive diapause, with which the beetle adjusts its life cycle to local climate and host-plant phenology. The beetle lines were collected from 18 sites in Japan. The diapause incidence under a photoperiodic condition of 13 h light : 11 h dark (LD 13:11) and the critical day length differed among the beetle lines. Analysis with the generalized linear model showed that latitude, altitude and host-plant species ( Ambrosia artemisiifolia vs. Ambrosia trifida) had significant effects on diapause incidence under LD 13:11. These results suggest that the O. communa populations have rapidly adapted to local environmental conditions after their colonization. However, the photoperiodic response of the O. communa population in Tomakomai, the northernmost part of its distribution range in Japan, deviated significantly from the general trend. We suggest that this deviation is attributed to either: (i) that this beetle has colonized Tomakomai more recently compared to the other sites; or (ii) that the Tomakomai population has adapted to local environments in a different way from other populations. [ABSTRACT FROM AUTHOR]

The biology of the gram blue butterfly, Euchrysops cnejus (Fabricius) (Lycaenidae: Lapidoptera) and its relationship with the phenology of host plant cowpea, Vigna unguiculata L. (Fabaceae) were studied. Eggs were reared under the laboratory conditions at 28 ± 2°C and 74 ± 3% RH. The incubation period of the eggs found to be 2.33 ± 0.51 days, larval developmental period 14.65 ± 0.51 days, pre-pupal period 0.30 ± 0.04 day and pupal period 5.66 ± 0.51 days. The species took 22.94 ± 0.55 days for development from egg to adult under the laboratory condition. The length of 1st, 2nd, 3rd and 4th instar larvae was 3.66 ± 0.40, 6.16 ± 0.51, 12.16 ± 0.51 and 15.33 ± 0.40 mm, respectively. The pre-pupal length was 9.16 ± 0.61 mm and the pupal length was 9.08 ± 0.37 mm. The host-plant occurs in the field from February to July. The butterfly appeared in March. The coincidence of the gram blue butterfly to its host-plant occurred between April and early July. The oviposition behaviour, incubation and immature stages were found to be profoundly related with host plant-phenological phases. [ABSTRACT FROM AUTHOR]

Global analyses of interspecific interactions are rapidly increasing our understanding of patterns and processes at large scales. Understanding how biodiversity assembles and functions on a global scale will increasingly require analyses of complex interactions at different ecological and phylogenetic levels. We present an analysis of host-plant associations in the sap-sucking Psylloidea (∼3,800 species) using the most comprehensive assemblage of host data for this group compiled from 66 % of published records. Psyllids are known for high levels of host specificity and host switching between related plants at local scales, but a global survey implicates historical processes that are not entirely consistent with those at local scales. In particular, saltationary host switching events appear to have been a key factor explaining the wide but patchy distribution of psyllid host-plants throughout the angiosperm phylogeny. Alternative explanations involving co-diversification with subsequent extinction seem implausible. At the seed plant family level, we compare associations for psyllids with those of their relatives the aphids, but, despite notable differences in biogeographic distributions, find few plant families (2%) that host only psyllids but not aphids, while a much larger percentage (31%) host aphids but not psyllids, and 43% of plant families distributed throughout the plant phylogeny host neither group. [ABSTRACT FROM PUBLISHER]

Copyright of Biodiversity & Natural History is the property of Centro de Estudios de Biodiversidad and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of African Crop Science Journal is the property of African Crop Science Journal and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Most crop pests find a suitable host through chemical cues released from plants, but little is known about the odorscape encountered by host-seeking gravid females under natural, outdoor conditions. In this field study, the volatile organic compound (VOC) composition of maize ( Zea mays, L.), a host for the European corn borer (ECB) ( Ostrinia nubilalis Hüb.) was characterized during the oviposition flight and compared with a forest odorscape. VOCs from maize fields and the forest atmosphere were collected by solid phase microextraction and characterized by gas chromatography-mass spectrometry. The electroantennographic (EAG) response of female ECB antennae to candidate VOCs was tested. Analyses revealed clear differences between the maize field and the forest odorscapes, mainly composed of ubiquitous VOCs but in specific ratios. The maize field odorscape is more complex than the forest odorscape for maize found 18 VOCs but only eight in the forest. Both biotopes shared seven VOCs-green leaf volatiles (GLV), monoterpènes (MT) and homoterpenes. In addition, we found in the forest a distinctive sesquiterpene (SQT) identified as isoledene. The highest EAG responses were elicited by two GLVs and a MT shared by the two biotopes. SQT elicited weak EAG responses, except β-farnesene, only found in the maize field odorscape. Our results suggest that the two biotopes produce specific chemical signatures that insects may use as host cues. To the best of our knowledge this paper is the first report on the maize odorscapes under field conditions. The putative role of the VOCs in host plant detection and selection is discussed. [ABSTRACT FROM AUTHOR]

1. Biological invasions bring together formerly isolated insect taxa and allow the study of ecological interactions between species with no coevolutionary history. Among polyphagous insects, such species may competitively exclude each other unless some form of niche partitioning allows them to coexist. 2. In the present study, we investigate whether the ability to exploit different fruits can increase the likelihood of coexistence of four species of polyphagous Tephritidae, one endemic and three successive invaders, in the island of La Réunion. In the laboratory, we studied the performances of all four species on the four most abundant fruit resources in the island, as well as the relative abundances of fly species on these four fruit species in the field. We observe no indication of niche partitioning for any of the four abundant fruits. 3. Analyses of an extensive field data series suggest that: (i) the four fly species largely overlap in fruit exploitation, once climatic effects are accounted for; (ii) however, one species ( Ceratitis capitata) can exploit rare fruit species that are not exploited by others present in the same climatic niche; and (iii) the endemic species C. catoirii, now nearly extinct in La Réunion, has no private niche with respect to either climatic range or fruit use. 4. On the whole, with the possible exception of C. capitata, the results point to a limited role of fruit diversity in encouraging coexistence among polyphagous tephritids recently brought into contact by accidental introductions. [ABSTRACT FROM AUTHOR]

In the Midwestern United States, more than 99.99% of pre-settlement oak (Quercus) savanna has been lost due to agriculture and fire suppression. Thus, the restoration of this ecosystem is imperative to secure the biodiversity, which depends on oak savanna. In this study, we characterized factors affecting the host-plant quality and nectar use of the endangered Karner blue butterfly (Lycaeides melissa samuelis Nabokov) in Ohio. Past research has shown butterfly abundance to be correlated with host-plant quantity, habitat area, and nectar plant abundance. However, there is growing recognition that host-plant quality is important at small spatial scales. We measured host-plant quality by quantifying leaf nitrogen content for the first larval brood and a PCA analysis of nitrogen and water content for the second larval brood. Additionally, observations quantified adult female foraging rates. Our results for the first brood larval stage found no significant difference in leaf nitrogen between burned, mowed, and unmanaged treatments. We used Akaike's Information Criteria (AIC) to determine that host-plant quality for the second brood was primarily explained by herbaceous vegetation density followed by canopy cover and aspect. Greater herbaceous vegetation density, greater canopy cover, and flat/north aspects were associated with higher quality host-plants. Lower host-plant nitrogen for the second brood was accompanied by a greater adult foraging rate. Management of Karner blue habitats should include restoring areas with a compatible herbaceous structure and increasing historically abundant forbs, which provide nectar to second brood Karner blues. This ecosystem-based management should positively impact many species in this rare oak savanna community. [ABSTRACT FROM AUTHOR]

In this paper we demonstrate a UV-B-mediated link between host plants, herbivores and their parasitoids, using a model system consisting of a host plant Brassica oleracea, a herbivore Plutella xylostella and its parasitoid Cotesia plutellae. Ultraviolet-B radiation (UV-B) is a potent elicitor of a variety of changes in the chemistry, morphology and physiology of plants and animals. Recent studies have demonstrated that common signals, such as jasmonic acid (JA), play important roles in the mechanisms by which plants respond to UV-B and to damage by herbivores. Plant responses elicited by UV-B radiation can affect the choices of ovipositing female insects and the fitness of their offspring. This leads to the prediction that, in plants, the changes induced as a consequence of UV damage will be similar to those elicited in response to insect damage, including knock-on effects upon the next trophic level, predators. In our trials female P. xylostella oviposited preferentially on host plants grown in depleted UV-B conditions, while their larvae preferred to feed on tissues from UV-depleted regimes over those from UV-supplemented ones. Larval feeding patterns on UV-supplemented tissues met the predictions of models which propose that induced defences in plants should disperse herbivory; feeding scars were significantly smaller and more numerous – though not significantly so – than those on host plant leaves grown in UV-depleted conditions. Most importantly, female parasitoids also showed a clear pattern of preference when given the choice between host plants and attendant larvae from the different UV regimes; however, in the case of the female parasitoids, the choice was in favour of potential hosts foraging on UV-supplemented tissues. This study demonstrates the potential for UV-B to elicit a variety of interactions between trophic levels, most likely mediated through effects upon host plant chemistry. [ABSTRACT FROM AUTHOR]

The European grapevine moth, Lobesia botrana (Lepidoptera: Tortricidae), is a polyphagous insect able to develop on grapes and wild plants. We tested the hypothesis that the parasitoid Dibrachys cavus (Hymenoptera: Pteromalidae) uses the larval frass in its host search. A two-armed olfactometer was used to measure the attractiveness of L. botrana larvae, their silk, or their frass after larvae were fed on different host plants. Frass of three Lepidoptera ( L. botrana, Eupoecillia ambiguella, Sphinx ligustri) and one Orthoptera ( Chorthippus brunneus) was assayed, but only L. botrana was used to test an effect of the larval host plant (two grape cultivars and three other plant species) to D. cavus females. Larvae without frass did not attract D. cavus whatever their origin, but their frass was attractive at a dose of 2–3 days equivalent of larval frass production. The silk produced by a single larva ( L. botrana) was not attractive to D. cavus. The parasitoid was most attracted to the odor of S. ligustri; the frass of L. botrana was more attractive than that of E. ambiguella, irrespective of the species on which D. cavus had been reared. There was no difference in attractiveness of frass collected from L. botrana raised on food containing different plants. Chemical extracts using five different polarity solvents (acetone, dichloromethane, hexane, methanol, and water) differed in attractiveness to D. cavus. Water and dichloromethane were the most attractive. This suggests that a complex volatile signal made from intermediate to polar volatiles may be involved in attraction. D. cavus used frass to discriminate between different potential host species. Our results revealed that the larval food of L. botrana did not modify frass attractiveness, but that the moth species did. [ABSTRACT FROM AUTHOR]