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Background The widespread nature of coronavirus disease 2019 (COVID-19) has been unprecedented. We sought to analyze its global impact with a survey on colorectal cancer (CRC) care during the pandemic. Methods The impact of COVID-19 on preoperative assessment, elective surgery, and postoperative management of CRC patients was explored by a 35-item survey, which was distributed worldwide to members of surgical societies with an interest in CRC care. Respondents were divided into two comparator groups: 1) ‘delay’ group: CRC care affected by the pandemic; 2) ‘no delay’ group: unaltered CRC practice. Results A total of 1,051 respondents from 84 countries completed the survey. No substantial differences in demographics were found between the ‘delay’ (745, 70.9%) and ‘no delay’ (306, 29.1%) groups. Suspension of multidisciplinary team meetings, staff members quarantined or relocated to COVID-19 units, units fully dedicated to COVID-19 care, personal protective equipment not readily available were factors significantly associated to delays in endoscopy, radiology, surgery, histopathology and prolonged chemoradiation therapy-to-surgery intervals. In the ‘delay’ group, 48.9% of respondents reported a change in the initial surgical plan and 26.3% reported a shift from elective to urgent operations. Recovery of CRC care was associated with the status of the outbreak. Practicing in COVID-free units, no change in operative slots and staff members not relocated to COVID-19 units were statistically associated with unaltered CRC care in the ‘no delay’ group, while the geographical distribution was not. Conclusions Global changes in diagnostic and therapeutic CRC practices were evident. Changes were associated with differences in health-care delivery systems, hospital’s preparedness, resources availability, and local COVID-19 prevalence rather than geographical factors. Strategic planning is required to optimize CRC care., Global changes in both diagnostic and therapeutic practices in colorectal cancer care were evident in this survey conducted to analyze the impact of COVID-19 outbreak. The importance of this finding is that changes were associated with differences in health care delivery systems, hospital’s preparedness, resources availability, and local COVID-19 prevalence rather than geographical variations.

Environmental lead contamination negatively impacts human, animal, and ecosystem health, yet there is a lack of research in this area that incorporates a One Health framework – examining co-exposures among species through their shared environment. The purpose of this study was to integrate human and animal data with public soil lead levels to better understand lead exposure patterns across species in an urban US city. Over 200 soil samples were collected, analyzed for lead, and mapped in combination with other risk factors pulled from the literature to identify areas of highest risk. Human socio-demographic data, dog, and house sparrow density data were mapped to investigate the association between these variables and soil lead levels. Geospatial analysis software was used to visualize the geospatial distribution of soil lead levels and known risk factors for environmental lead contamination, and a block group risk score was calculated and mapped. Associations between human and animal-associated variables and soil lead levels and block risk scores were assessed using Spearman's correlations. Positive, statistically significant associations were found between soil lead levels and higher population density, higher education levels, and higher median household income. Areas with higher soil lead levels and lead exposure risk scores were associated with greater dog density and greater house sparrow density. This study fills an important knowledge gap on the risk of environmental lead exposure to humans, domestic animals, and wildlife., Graphical abstract Unlabelled Image, Highlights • Environmental lead similarly threatens human, domestic and wild urban inhabitants. • Environmental lead exposure is a prime field for One Health assessment. • There is a need to expand our understanding of ecosystem health threats. • Public soil lead levels sometimes exceeded state and federal thresholds for healthy soil. • Soil as an exposure source for humans and animals is underassessed.

Anopheles coluzzii females, important malaria vectors in Africa, mate only once in their lifetime. Mating occurs in aerial swarms with a high male-to-female ratio, where traits underlying male mating success are largely unknown. Here, we investigated whether cuticular hydrocarbons (CHCs) influence mating success in natural mating swarms in Burkina Faso. As insecticides are widely used in this area for malaria control, we also determined whether CHCs affect insecticide resistance levels. We find that mated males have higher CHC abundance than unmated controls, suggesting CHCs could be determinants of mating success. Additionally, mated males have higher insecticide resistance under pyrethroid challenge, and we show a link between resistance intensity and CHC abundance. Taken together, our results suggest that CHC abundance may be subject to sexual selection in addition to selection by insecticide pressure. This has implications for insecticide resistance management, as these traits may be sustained in the population due to their benefits in mating even in the absence of insecticides., In this study, Adams et al. investigate the effect of cuticular hydrocarbons on mating success in natural mosquito mating swarms. These hydrocarbons confer both higher mating success and increased resistance to pyrethroid, suggesting sexual selection for insecticide resistance in this population secondary to mating success.

Orangutans are noteworthy among great apes in their predilection for chronic, insidious, and ultimately fatal respiratory disease. Termed Orangutan Respiratory Disease Syndrome (ORDS), this cystic fibrosis–like disease is characterized by comorbid conditions of sinusitis, mastoiditis, airsacculitis, bronchiectasis, and recurrent pneumonia. The aim of this retrospective study was to determine the sensitivity of clinical signs in the diagnosis of ORDS in Bornean orangutans (Pongo pygmaeus) compared with the gold standard for diagnosis via computed tomography (CT). We retrospectively compared observed clinical signs with CT imaging in a population of clinically affected animals at an orangutan rescue center in southeastern Borneo. From August 2017 to 2019, this center housed 21 ORDS-affected animals, all of which underwent CT imaging to delineate which areas of the respiratory tract were affected. We reviewed clinical signs recorded in medical records and keeper observation notes for each individual for the period of 2 years prior to the date of the CT scan. A chi-square test of association was used to assess whether the observed clinical signs could predict the results of CT imaging. Results show that clinical signs may not be sensitive indicators in predicting respiratory disease identified by CT imaging. Based on the results of this study, clinical signs appear to be very poor predictors of underlying respiratory pathology in orangutans, based on high P-values, low sensitivity, and low specificity. This result is observed even with clinical signs data gathered over a full 24-mo period prior to CT scan performance. The findings of this study suggest the need for advanced imaging to properly diagnose and manage the most common health issue of captive orangutans.

The reproductive fitness of the Anopheles gambiae mosquito represents a promising target to prevent malaria transmission. The ecdysteroid hormone 20-hydroxyecdysone (20E), transferred from male to female during copulation, is key to An. gambiae reproductive success as it licenses females to oviposit eggs developed after blood feeding. Here we show that 20E-triggered oviposition in these mosquitoes is regulated by the stress- and immune-responsive c-Jun N-terminal kinase (JNK). The heads of mated females exhibit a transcriptional signature reminiscent of a JNK-dependent wounding response while mating — or injection of virgins with exogenous 20E — selectively activates JNK in the same tissue. RNAi-mediated depletion of JNK pathway components inhibits oviposition in mated females, whereas JNK activation by silencing the JNK phosphatase puckered induces egg laying in virgins. Together, these data identify JNK as a potential conduit linking stress responses and reproductive success in the most important vector of malaria.

Anopheles gambiae and An. coluzzii, the two most important malaria vectors in sub-Saharan Africa, are recently radiated sibling species that are reproductively isolated even in areas of sympatry. In females from these species, sexual transfer of male accessory gland products, including the steroid hormone 20-hydroxyecdysone (20E), induces vast behavioral, physiological, and transcriptional changes that profoundly shape their post-mating ecology, and that may have contributed to the insurgence of post-mating, prezygotic reproductive barriers. As these barriers can be detected by studying transcriptional changes induced by mating, we set out to analyze the post-mating response of An. gambiae and An. coluzzii females captured in natural mating swarms in Burkina Faso. While the molecular pathways shaping short- and long-term mating-induced changes are largely conserved in females from the two species, we unravel significant inter-specific differences that suggest divergent regulation of key reproductive processes such as egg development, processing of seminal secretion, and mating behavior, that may have played a role in reproductive isolation. Interestingly, a number of these changes occur in genes previously shown to be regulated by the sexual transfer of 20E and may be due to divergent utilization of this steroid hormone in the two species.

Mating plugs promote malaria parasites Males of some of the malaria-transmitting mosquitoes “plug” females after copulation to stop interloping males from mating. The mating plug also delivers a steroid hormone into the female uterus. This hormone pulse promotes egg production and stimulates egg laying. It also curbs the mosquitoes' immune responses, which allows parasites such as malaria to develop unhindered. Mitchell et al. discovered that plugs are a recent evolutionary acquisition (see the Perspective by Alonzo). South American anopheline mosquitoes lack these plugs altogether, whereas African and Indian species have complex plugs replete with hormones. It is unlikely to be a coincidence that the most elaborate mosquito plugs are also found in regions where malaria transmission rates are highest. Science , this issue p. 985 ; see also p. 948

Transmission of malaria parasites occurs when a female Anopheles mosquito feeds on an infected host to acquire nutrients for egg development. How parasites are affected by oogenetic processes, principally orchestrated by the steroid hormone 20-hydroxyecdysone (20E), remains largely unknown. Here we show that Plasmodium falciparum development is intimately but not competitively linked to processes shaping Anopheles gambiae reproduction. We unveil a 20E-mediated positive correlation between egg and oocyst numbers; impairing oogenesis by multiple 20E manipulations decreases parasite intensities. These manipulations, however, accelerate Plasmodium growth rates, allowing sporozoites to become infectious sooner. Parasites exploit mosquito lipids for faster growth, but they do so without further affecting egg development. These results suggest that P. falciparum has adopted a non-competitive evolutionary strategy of resource exploitation to optimize transmission while minimizing fitness costs to its mosquito vector. Our findings have profound implications for currently proposed control strategies aimed at suppressing mosquito populations.

Many chemotherapeutic agents selectively target rapidly dividing cells, including cancer cells, by causing DNA damage that leads to genome instability and cell death. We used Drosophila melanogaster to study how mutations in key DNA repair genes affect an organism’s response to chemotherapeutic drugs. In this study, we focused on camptothecin and its derivatives, topotecan and irinotecan, which are type I topoisomerase inhibitors that create DNA double-strand breaks in rapidly dividing cells. Here, we describe two polymorphisms in Drosophila Cyp6d2 that result in extreme sensitivity to camptothecin but not topotecan or irinotecan. We confirmed that the sensitivity was due to mutations in Cyp6d2 by rescuing the defect with a wild-type copy of Cyp6d2. In addition, we showed that combining a cyp6d2 mutation with mutations in Drosophila brca2 results in extreme sensitivity to camptothecin. Given the frequency of the Cyp6d2 polymorphisms in publcly available Drosophila stocks, our study demonstrates the need for caution when interpreting results from drug sensitivity screens in Drosophila and other model organisms. Furthermore, our findings illustrate how genetic background effects can be important when determining the efficacy of chemotherapeutic agents in various DNA repair mutants.

Postcopulatory sexual selection is recognized as a key driver of reproductive trait evolution, including the machinery required to produce endogenous nuptial gifts. Despite the importance of such gifts, the molecular composition of the non-gametic components of male ejaculates and their interactions with female reproductive tracts remain poorly understood. During mating, male Photinus fireflies transfer to females a spermatophore gift manufactured by multiple reproductive glands. Here we combined transcriptomics of both male and female reproductive glands with proteomics and metabolomics to better understand the synthesis, composition and fate of the spermatophore in the common Eastern firefly, Photinus pyralis. Our transcriptome of male glands revealed up-regulation of proteases that may enhance male fertilization success and activate female immune response. Using bottom-up proteomics we identified 208 functionally annotated proteins that males transfer to the female in their spermatophore. Targeted metabolomic analysis also provided the first evidence that Photinus nuptial gifts contain lucibufagin, a firefly defensive toxin. The reproductive tracts of female fireflies showed increased gene expression for several proteases that may be involved in egg production. This study offers new insights into the molecular composition of male spermatophores, and extends our understanding of how nuptial gifts may mediate postcopulatory interactions between the sexes., Tuft University. Faculty Research Fund (FRAC (S.M.L.), Arnold and Mabel Beckman Foundation. Beckman Young Investigator, Pew Scholars Program in the Biomedical Sciences, Searle Scholars Program

While Darwin first conceptualized the connection between morphological trait variation across related taxa and mating system evolution nearly 150 years ago, a mechanistic understanding of the relationship between genes, physiology and behaviour across species has only recently become possible through remarkable progress in genetics and molecular biology. With their extensive diversification, ecological variation and burgeoning genomic resources, mosquitoes are an ideal group to identify patterns of trait variation and suggest causal evolutionary mechanisms. Here we discuss the mating systems of Anopheles gambiae and Aedes aegypti mosquitoes, vectors of major infectious diseases that afflict humanity. In this review, our emphasis is on interspecific comparisons of traits relevant to mechanisms of pre- and postcopulatory selection, including mating behaviour, molecular pathways of reproduction, postmating physiology and morphological traits. Based on a wealth of recent studies in mosquito genomics and phylogenetics, we provide an evolutionary context to examine adaptive changes in mosquito reproduction, their possible impact on pathogen transmission and their potential consequences for disease control.

Because females often mate with multiple males, it is critical to expand our view of sexual selection to encompass pre-, peri- and post-copulatory episodes to understand how selection drives trait evolution. In Photinus fireflies, females preferentially respond to males based on their bioluminescent courtship signals, but previous work has shown that male paternity success is negatively correlated with flash attractiveness. Here, we experimentally manipulated both the attractiveness of the courtship signal visible to female Photinus greeni fireflies before mating and male nuptial gift size to determine how these traits might each influence mate acceptance and paternity share. We also measured pericopulatory behaviours to examine their influence on male reproductive success. Firefly males with larger spermatophores experienced dual benefits in terms of both higher mate acceptance and increased paternity share. We found no effect of courtship signal attractiveness or pericopulatory behaviour on male reproductive success. Taken together with previous results, this suggests a possible trade-off for males between producing an attractive courtship signal and investing in nuptial gifts. By integrating multiple episodes of sexual selection, this study extends our understanding of sexual selection in Photinus fireflies and provides insight into the evolution of male traits in other polyandrous species.

In several insect species, seminal fluid proteins (SFPs) have been demonstrated to be key regulators of male and female fitness through their ability to alter female physiology and behaviour. Tribolium castaneum is an economically important pest species and a model system for sexual selection research, but little is known about SFPs in this insect. To create a foundation for the study of T. castaneum SFPs, we used mass spectrometry to identify putative SFPs by comparing proteins detected in the male reproductive glands with those found in the reproductive tracts of virgin and mated females. Fourteen putative SFPs, thirteen with male biased expression, were identified through this approach. We also used reverse transcription PCR (RT-PCR) to examine expression levels across different tissue types. We found strongly male-biased expression in 13 genes, nine of which were expressed only in male accessory gland tissue. This represents the first proteomic-based method of identifying putative SFPs in any coleopteran species, and is the first study in this species to identify putative SFPs that are likely transferred to the female. This work could lead to functional analyses of the role of SFPs in sexual selection, sexual conflict and potential control of a pest species.

Although the primary function of mating is gamete transfer, male ejaculates contain numerous other substances that are produced by accessory glands and transferred to females during mating. Studies with several model organisms have shown that these substances can exert diverse behavioural and physiological effects on females, including altered longevity and reproductive output, yet a comprehensive synthesis across taxa is lacking. Here we use a meta-analytic approach to synthesize quantitatively extensive experimental work examining how male ejaculate quantity affects different components of female fitness. We summarize effect sizes for female fecundity (partial and lifetime) and longevity from 84 studies conducted on 70 arthropod species that yielded a total of 130 comparisons of female fecundity and 61 comparisons of female longevity. In response to greater amounts of ejaculate, arthropod females demonstrate enhanced fecundity (both partial and lifetime) but reduced longevity, particularly for Diptera and Lepidoptera. Across taxa, multiply mated females show particularly large fecundity increases compared to singly mated females, indicating that single matings do not maximize female fitness. This fecundity increase is balanced by a slight negative effect on lifespan, with females that received more ejaculate through polyandrous matings showing greater reductions in lifespan compared with females that have mated repeatedly with the same male. We found no significant effect size differences for either female fecundity or longevity between taxa that transfer sperm packaged into spermatophores compared to taxa that transfer ejaculates containing free sperm. Furthermore, females that received relatively larger or more spermatophores demonstrated greater lifetime fecundity, indicating that these seminal nuptial gifts provide females with a net fitness benefit. These results contribute to our understanding of the evolutionary origin and maintenance of non-sperm ejaculate components, and provide insight into female mate choice and optimal mating patterns.

The beetle family Lampyridae (fireflies) encompasses ∼100 genera worldwide with considerable diversity in life histories and signaling modes. Some lampyrid males use reproductive accessory glands to produce spermatophores, which have been shown to increase female lifetime fecundity. Sexual dimorphism in the form of neotenic and flightless females is also common in this family. A major goal of this study was to test a hypothesized link between female flight ability and male spermatophore production. We examined macroevolutionary patterns to test for correlated evolution among different levels of female neoteny (and associated loss of flight ability), male accessory gland number (and associated spermatophore production), and sexual signaling mode. Trait reconstruction on a molecular phylogeny indicated that flying females and spermatophores were ancestral traits and that female neoteny increased monotonically and led to flightlessness within multiple lineages. In addition, male spermatophore production was lost multiple times. Our evolutionary trait analysis revealed significant correlations between increased female neoteny and male accessory gland number, as well as between flightlessness and spermatophore loss. In addition, female flightlessness was positively correlated with the use of glows as female sexual signal. Transition probability analysis supported an evolutionary sequence of female flightlessness evolving first, followed by loss of male spermatophores. These results contribute to understanding how spermatophores have evolved and how this important class of seminal nuptial gifts is linked to other traits, providing new insights into sexual selection and life-history evolution.

The black-winged firefly, Luciola cerata Olivier, is endemic to Taiwan and is the most common firefly on the island. Males flash spontaneously and females respond with bioluminescent flashes at fixed response delays. In order to explore the potential for sexual selection in L. cerata, we surveyed males at 12 sites in Taiwan. We measured variation in male morphological characteristics and mated males to females. Male flash behavior and mating success was quantified under a variety of experimental sex ratios in the lab. We found there are two male morphs of this species, which are distinguishable only by the morphology of the lantern. One morph has a pentagonal second light segment, while the other has a semi-oval second light segment and only produces a flash with the first lantern segment. Besides this difference in morphology, the flash patterns and mating behavior also differ between these two morphs. Males with a pentagonal segment have a faster flashing rate than those with a semi-oval segment and are considered more attractive to females in groups with male-biased sex ratios. Furthermore, females that mate with the pentagonal-segment morph demonstrate greater fecundity than those that mate with the semi-oval-segment morph.

Females often show a preference for exaggerated male sexual traits or courtship behaviors. Such preferences can benefit females if trait expression is correlated with male genetic quality or phenotypic condition. Previous studies of several Photinus fireflies have revealed considerable intraspecific variation in the bioluminescent courtship signals emitted by males, and have also demonstrated that females prefer more conspicuous male signals. Thus, females might gain information about male phenotypic quality if courtship signals reflect male condition. We examined possible condition-dependence of Photinus male courtship signals using two complementary approaches. First we experimentally manipulated male mating status, which is expected to affect male condition by depleting resources required for nuptial gift formation, and looked at how individual male flash signals changed with mating status and over time. We used an additional approach to assess condition-dependence by examining whether a relationship exists between flash signal parameters and measures of male condition and body shape. We found that the pulse rate of P. greeni courtship signals was not altered by male mating status or age, and that the pulse duration of P. ignitus signals was also not affected by male mating status. In P. pyralis fireflies, males showed a non-significant trend toward reduced signal pulse duration with age. When we examined the relationship between male flash signals and condition measures, we found no effect of male condition or body shape on courtship signals in P. greeni or P. ignitus; in P. pyralis, males with wider body shapes produced longer duration flash signals. On the other hand, we found no evidence in P. pyralis that condition predicted flash duration. Taken together, these results indicate that Photinus males’ flash signals do not reflect adult male condition, and suggest that females are unlikely to use courtship signals as an indicator of male phenotypic quality.

During animal courtship, multiple signals transmitted in different sensory modalities may be used to recognize potential mates. In fireflies (Coleoptera: Lampyridae), nocturnally active species rely on long-range bioluminescent signals for species, sex, and mate recognition, while several diurnally active species rely on pheromonal signals. Although in many insects non-volatile cuticular hydrocarbons (CHC) also function in species and sex discrimination, little is known about the potential role of CHC in fireflies. Here, we used gas chromatography to characterize species and sex differences in the CHC profiles of several North American fireflies, including three nocturnal and two diurnal species. Additionally, we conducted behavioral bioassays to determine whether firefly males (the searching sex) were differentially attracted to extracts from conspecific vs. heterospecific females. Gas chromatography revealed that nocturnal Photinus fireflies had low or undetectable CHC levels in both sexes, while diurnal fireflies showed higher CHC levels. No major sex differences in CHC profiles were observed for any firefly species. Behavioral bioassays demonstrated that males of the diurnal firefly Ellychnia corrusca were preferentially attracted to chemical extracts from conspecific vs. heterospecific females, while males of the remaining species showed no discrimination. These results suggest that while CHC may function as species recognition signals for some diurnal fireflies, these compounds are unlikely to be important contact signals in nocturnal Photinus fireflies.

During mating, many male insects transfer sperm packaged within a spermatophore that is produced by reproductive accessory glands. While spermatophores have been documented in some North American fireflies (Coleoptera: Lampyridae), little is known concerning either production or transfer of spermatophores in the aquatic Luciola fireflies widespread throughout Asia. We investigated this process in Japanese Luciola lateralis and L. cruciata by feeding males rhodamine B, a fluorescent dye known to stain spermatophore precursors. We then mated males with virgin females, and dissected pairs at various timepoints after mating. In both of these Luciola species, spermatophores were produced by three pairs of male accessory glands and were transferred to females during the second stage of copulation. Male spermatophores were highly fluorescent, and were covered by a thin outer sheath; a narrow tube leading from an internal sperm-containing sac fit precisely into the female spermathecal duct, presumably for sperm delivery. Both L. lateralis and L. cruciata females have a spherical spermatheca as well as a highly extensible gland where spermatophore breakdown commences by 24 h post-mating. Similar reproductive anatomy was observed for both sexes in Luciola ficta from Taiwan. These results suggest that nuptial gifts may play an important role in many firefly-mating systems.

Sperm competition is a fundamentally important component ofpostcopulatory sexual selection, and direct removal of rival malesperm from the female reproductive tract has been documented inat least three insect orders: Odonata, Orthoptera and Coleoptera(e.g. Siva-Jothy 1987; Ono et al. 1989; Gage 1992; Simmons 2001).Haubruge et al. (1999) reported a novel twist on sperm removal,a process they termed fertilization by proxy, in the red flour beetleTribolium castaneum. This study suggested that not only do malesremove previously stored sperm from females, but that males alsotranslocate rival males’ sperm when they subsequently mate withnew females. The mechanism they proposed was rival spermremoval by an array of chitinous spines located on the matingmale’s aedeagus, followed by translocation of these still viablesperm when this male subsequently mated with another female.Empirical evidence for this novel phenomenon was based ona physiological paternity marker involving resistance to the insec-ticide malathion, which in T. castaneum is due to a spontaneousmutation in a carboxylesterase enzyme that confers malathion-specific resistance (Dyte & Rowlands 1968; White & Bell 1988;Haubruge et al. 2002; Arnaud et al. 2005). The experimental designincludedthreeconsecutivecrosses:(1)amalathion-resistantvirginmalewasmatedwithamalathion-susceptiblevirginfemale,(2)thesame susceptible female was mated with a susceptible virgin maleand (3) the same susceptible male was mated with a new suscep-tible virgin female. Adult progeny collected from the two matedfemales were subjected to an insecticide-exposure bioassay(contact with 1% malathion in acetone) for 3 h. Paternity wasassigned based onwhether progeny died (indicating they had beensired by the directly mating, susceptible male) or survived(presumed to be sired indirectly by the resistant male). Haubrugeet al. (1999) reported that fertilization by proxy was quite common(occurring in 22% of sequential matings), and that in such cases,a surprisingly high percentage (53% on average) of offspring weresired by translocated sperm.To date, this study by Haubruge et al. (1999) remains the onlyevidence for rival sperm translocation, a phenomenon that couldpotentially counteract any fitness advantages that males may gainfrom sperm removal. As pointed out recently by Kelly (2006),replication studies traditionally have been undervalued in behav-ioural ecology, and consequently both confirmatory and contra-dictory results may be difficult to publish. However, verification ofkey empirical results should be standard operating procedure torigorously test any novel evolutionary hypotheses. Based on theimportant evolutionary implications of the phenomenon of spermtranslocation, we conducted a partial replication of the study byHaubruge et al. (1999), in which we exactly duplicated mostexperimental procedures but used a different paternity marker todifferentiate between the two potential sires.

Many chemotherapeutic agents selectively target rapidly dividing cells, including cancer cells, by causing DNA damage that leads to genome instability and cell death. We used Drosophila melanogaster to study how mutations in key DNA repair genes affect an organism’s response to chemotherapeutic drugs. In this study, we focused on camptothecin and its derivatives, topotecan and irinotecan, which are type I topoisomerase inhibitors that create DNA double-strand breaks in rapidly dividing cells. Here, we describe two polymorphisms in Drosophila Cyp6d2 that result in extreme sensitivity to camptothecin but not topotecan or irinotecan. We confirmed that the sensitivity was due to mutations in Cyp6d2 by rescuing the defect with a wild-type copy of Cyp6d2. In addition, we showed that combining a cyp6d2 mutation with mutations in Drosophila brca2 results in extreme sensitivity to camptothecin. Given the frequency of the Cyp6d2 polymorphisms in publcly available Drosophila stocks, our study demonstrates the need for caution when interpreting results from drug sensitivity screens in Drosophila and other model organisms. Furthermore, our findings illustrate how genetic background effects can be important when determining the efficacy of chemotherapeutic agents in various DNA repair mutants.

Many insect taxa show conspicuous sexual dimorphism in which females lack functional wings and are therefore incapable of flight. In fireflies, this loss of female flight is correlated with male production of spermatophore nuptial gifts, with species with flightless females also lacking gift production. In this study we further examined the relationship between sexual dimorphism and nuptial gifts by examining the reproductive ecology of two Asian fireflies, the sexually monomorphic Aquatica ficta (Luciolinae) and dimorphic Pyrocoelia pectoralis (Lampyrinae). We describe the reproductive anatomy of P. pectoralis males and females, and the time course of A. ficta spermatophore transfer. Through a series of mating experiments, we determined the effect of the number of matings on female fecundity, egg hatching success and female lifespan. The spermatophore-producing A. ficta was found to be monandrous, and female lifespan doubled as a result of that single mating. P. pectoralis was found to lack spermatophores but females were polyandrous and fecundity and egg hatching success both increased with additional matings. These results contradict patterns known from North American firefly species and provide insight into the role of male-derived substances in mating systems.

Animal nuptial gifts display multitudinous forms, and such gifts are especially interesting because they sit at the intersection of sexual selection, foraging ecology, and life-history evolution. However, even though such gifts are likely to play key roles in sexual selection and conflict, remarkably little is known about the selective agents responsible for their origin and maintenance. In this chapter, we propose a classification scheme based on (1) how gifts are produced (endogenous vs. exogenous) and also (2) how they are absorbed by the recipient (oral, genital, or transdermal). This classification provides a conceptual framework that should prove useful for formulating and testing predictions about how different gift types affect fitness of both males and females. Moving beyond earlier work that had coerced potential benefits to gift-giving males into the falsely dichotomous categories of parental investment versus mating effort, we illustrate how nuptial gifts might enhance male fitness across multiple selection episodes that occur before, during, and after mating. Finally, we highlight a few studies that have used comparative phylogenetic methods to see how nuptial gifts and other life-history traits may have changed over evolutionary time. One such study analyzed the evolutionary trajectories of spermatophore gifts within firefly beetles (Coleoptera: Lampyridae), revealing that male gifts have undergone correlated evolution with female flight ability. Thus, this study supports the idea that shifts in female resource allocation may potentially drive male investment in nuptial gifts. Looking forward, phylogenetic analyses across different taxonomic groups will be needed to provide insight into the evolutionary origin and maintenance of nuptial gifts. By including relevant ecological and life-history traits associated with resource allocation, such studies will undoubtedly expand our understanding of nuptial gift evolution.