Conspecific Females Research Articles

Mismatch in receiver responses to multimodal signals in a diurnal gecko

Multimodal signals are used by many animals for intraspecific communication and can provide information about sex identity as well as quality of the signaller. In diurnal geckos of the genus Cnemaspis, chromatic colour patches in males evolved after chemical secretions, providing us with an opportunity to examine the utility of evolving multimodality. We quantified signal components and receiver responses in Cnemaspis mysoriensis to determine the relative importance of chemical and visual traits for intraspecific communication. Digital imagery and spectrophotometry of lizards revealed the presence of two distinct male morphs (yellow-gular and white-gular) and one female form (white-gular). All males, but no females, had yellow eye rims. Characterization of chemical secretions from the ventral precloacal and femoral glands of all lizard forms revealed no differences between male morphs. However, all males differed from females in a few key compounds. We then exposed lizards to only chemical stimuli, only visual stimuli, or both chemical and visual stimuli of conspecific males and females. We found that females were responsive to the chemical stimuli alone as well as the multimodal stimuli of males, whereas males were only responsive to the multimodal stimuli of other males. Neither chemical or visual components of females elicited a response from conspecifics. Thus, while the chemical secretions of males are sufficient for females to elicit a response, multimodal stimuli are necessary for males to respond. Based on variation in signalling traits and receiver responses, we conclude that: (1) chemical secretions signal both sex identity and male quality; (2) eye rim colour encodes information about sex identity; and (3) gular colour in males is probably not a redundant trait, providing some information to males, but not females. We conclude that the secondary evolution of visual signals in C. mysoriensis therefore enhances male–male social interactions and not communication in general.

Male attraction to female airborne cues by the net-casting spider, Deinopis spinosa

For many animals, finding a mate can be a difficult task. For males, it often involves actively searching for conspecific females, sometimes over great distances. This mate-searching can be aided through chemical or visual signals or cues produced by sexually receptive females. Here, we investigate the roles of olfaction and vision in mate-searching in a strictly nocturnal net-casting spider, Deinopis spinosa. First, we used an olfactometer assay to determine if mature male D. spinosa respond to conspecific airborne cues. We found that mature males, but not mature females, were attracted to airborne cues of mature female conspecifics. We next investigated the relative importance of olfaction and vision in male mate-searching. While manipulating airflow and light levels in screened enclosures in the laboratory, we tested freely moving mature males for mate-searching success. We found no effect of our airflow treatment on mate-searching success. Light levels, however, affected mate-searching in an unexpected way - males were more likely to locate females in complete darkness when compared to dim-light conditions. Our results suggest that visual cues are not necessary for successful male mate-searching in D. spinosa, but that the visual environment can nonetheless influence male behavior. In summary, we provide evidence suggesting that airborne cues, but not visual cues, are important in D. spinosa male mate-searching efforts, though the source of these chemical airborne cues remains unknown.

Oviposition Deterrents in Larval Frass of Potato Tuberworm Moth, Phthorimaea operculella (Lepidoptera: Gelechiidae).

The potato tuberworm moth (PTM) Phthorimaea operculella (Zeller) (Lepidoptera: Gelechiidae) is one of the most damaging pests of potato Solanum tuberosum L. in warm temperate and subtropical areas. Our previous experiment showed that extracts of larval frass of PTM deterred oviposition of conspecific females. In this study, we investigated the identification of chemicals in larval frass that were influencing the oviposition of PTM by behavioral bioassays and electroantennography analysis in the laboratory. Frass was collected from third and fourth instar larvae and combined analysis of gas chromatography coupled with electroantennography (GC-EAD) of dichloromethane extracts showed that eight compounds from larval frass extracts elicited repeatable antennal responses from mated females. Seven EAD-active compounds in frass volatile extract were identified by gas chromatography-mass spectrometry (GC-MS) as linoleic acid, octadecanoic acid, tricosane, pentacosane, heptacosane, nonacosane, and cholesterol. Oviposition bioassays indicated that frass extracts had a deterrent effect on egg laying, the deterrent activity increased with the concentration of frass extracts, and the threshold value for statistical significance in oviposition deterrence was in the range of 20-200mg frass per cage. Linoleic acid, pentacosane, heptacosane, nonacosane, and cholesterol in larval frass volatiles were found to play a key role in repelling oviposition in a dose-dependent manner. We suggest that the bioactive compounds in larval frass are responsible for repelling oviposition of PTM, and n-alkanes, especially pentacosane, strongly deter oviposition and may be considered as a potential oviposition deterrent for potential applications.

Chemical Signals of Conspecifics and Their Role in Seasonal Relationships in the Mongolian Hamster (Allocricetulus curtatus) (Cricetinae, Rodentia)

Abstract—The hormonal response of Mongolian hamster Allocricetulus curtatus males to the urine and midventral gland secretion (MVGS)) of conspecific females during several seasons was studied. The animals were kept under natural photoperiod and temperature. In autumn no significant changes in the testosterone level in the blood of males in response to any of the exposed signals were observed. In winter and summer, this parameter increased in response to the diestrous female odors of urine and MVGS . In the spring the urine of conspecific estrous females stimulated a significant increase in the levels of both testosterone and cortisol. Moreover, the cortisol level did not increase in response to exposure of the odors of diestrous females in any season of the year. The level of progesterone significantly increased only when MVGS was exposed in the spring and summer periods, and the absolute values of this parameter were significantly higher in spring than in summer. Differences in responses to chemical signals in two closely related species (Eversmann’s and Mongolian hamsters) are discussed in connection with the peculiarities of the intraspecific social relationships.

Behavioral and physiological response of male Callisphyris apicicornis (Coleoptera: Cerambycidae) to virgin con-specific females’ extracts

Callisphyris apicicornis (Fairmaire & Germain) (Coleoptera: Cerambycidae: Necydalinae) is a native, xylophagous, and polyphagous longhorned beetle, currently having the status of an increasing pest in some fruit orchards in Chile which needs a control strategy. However, no efficient methods have been developed against C. apicicornis. Since pheromone- based strategies are promissory against these types of pests, it is necessary to understand the chemical communication within this species in order to collect and identify the pheromonal compounds as the first step to develop pheromone- based control tactics. The objectives of this work were to study behavioral and electrophysiological responses of males to con-specific females and its extracts, to seek out evidence of chemical communication in the intraspecific relationship of C. apicicornis. In field, we collected 112 males using 8 baited traps with alive females in two separate experiments. However, neither males nor headspace (HS) extracts were attractive for either sex in field, no males were captured in those treatments (16 traps). On the other hand, in laboratory bioassays males showed significant electroantennographic responses to females’ volatiles extracts (1.46 mV) and gland extracts (1.15 mV). Likewise, behavioral bioassay showed significant olfactometric preference for females’ volatiles and gland extracts. Our results strongly suggest a female- produced sex attractant occurs within this species, so further studies should attempt to identify and quantify the chemicals compounds with this role

ASSESSMENT OF A VISUAL SCORING SYSTEM FOR IDENTIFYING AND QUANTIFYING ANEMIA IN MALE EASTERN BOX TURTLES ( TERRAPENE CAROLINA CAROLINA).

The North Carolina State University College of Veterinary Medicine Turtle Rescue Team (TRT) regularly admits wild eastern box turtles (EBT) ( Terrapene carolina carolina) for treatment and rehabilitation. Adult males of this species generally have an impressive red coloration of the iris, a feature commonly used to differentiate them from their brown-eyed female conspecifics. Male EBTs that present often display marked pallor of the eyes, which has accompanied clinical anemia. The aim of this study was to examine the relationship between eye color and packed cell volume (PCV) in adult male EBTs, and to assess the accuracy of using eye color to predict PCV. Eye-color scoring cards were created using Adobe Creative Cloud Photoshop®. Each card was composed of blocks displaying progressively lighter tints of a red hue, with a number (score) assigned to each block. Five-block, six-block, and nine-block scoring cards were prepared, with lower numbers (scores) corresponding to lighter hues. To determine the variation in subjective color scores assigned by different human observers, 85 individuals were asked to score EBT eye color in three animals using each of the three scoring cards. Eye color of adult male EBTs that presented to the TRT ( n = 18) and those housed at the North Carolina Museum of Natural Sciences ( n = 6) were scored using each of the three cards, immediately preceding venipuncture of the occipital sinus for determination of PCV. All animals were scored by at least two individuals. Turtles with low scores (pale eyes) using all three scoring cards consistently had lower PCVs. The five- and six-block scorecards had a positive predictive value (PPV) of 100% while the nine-block score card had a PPV of 71.4%. This specific and noninvasive method for estimating PCV of male EBTs is clinically desirable in both rehabilitation and hospital settings.

Inferring species boundaries using acoustic and morphological data in the ground cricket genus Gymnogryllus (Orthoptera: Grylloidea: Gryllinae)

An important function of song production by male crickets is to attract conspecific females. These sound signals can be used to infer species boundaries as they can provide indirect evidence for reproductive isolation. However, many studies of orthopteran diversity in South-east Asia are based mainly on morphology and only occasionally acoustics. As such, there is a lack of information on how acoustic data can be congruent with morphological data when used to delineate species. Crickets of the genus Gymnogryllus (Grylloidea, Gryllidae), are such an example. Gymnogryllus are relatively speciose, but their calling songs have not been studied. We collected specimens and calling songs of five Gymnogryllus species from South-east Asia. The acoustic parameters of the calls, along with male tegminal venation and morphology genitalia, were compared. All data types showed congruency in distinguishing G. sylvestris and G. leucostictus from each other and from the other species. Inferring species boundaries for G. angustus, G. malayanus, and G. unexpectus using acoustics and tegminal morphometry proves to be more challenging. While acoustics, tegminal morphometry, and genital morphology are likely to be useful for inferring species of Gymnogryllus from different species groups, greater coverage of taxa is needed to resolve taxonomy of closely related Gymnogryllus.

Floral synomone diversification of Bulbophyllum sibling species (Orchidaceae) in attracting fruit fly pollinators

Floral scent is one of the crucial cues to attract specific groups of insect pollinators in angiosperms. We examined the semiochemical diversity in the interactions between “fruit fly orchids” and their pollinator fruit fly species in two genera, Bactrocera and Zeugodacus (Tephritidae: Diptera). Two known attractants for the Dacini fruit flies, methyl eugenol (ME) and raspberry ketone (RK), have been identified from the Bulbophyllum orchids. Additionally, zingerone (ZN), with a hybrid chemical structure between ME and RK, and attracts both ME- and RK-sensitive fly species, was also identified. Male flies utilize the floral scent as sex pheromone precursor or components to attract conspecific females and gain mating advantage. We analyzed the floral components of two sibling orchids, Bulbophyllum macranthum collected from Southeast-Asian countries and Bu. praetervisum collected from Sabah, Malaysia. For Bu. macranthum, the major floral component from Malaysia and Thailand was identified as ZN; whereas that from the Philippines was ME. For Bu. praetervisum, RK was found as the major constituent, but chemical profiles of the attractants were different among individuals, i.e. in addition to RK, ZN was also found in some of the Bu. praetervisum flowers; and one of the specimens contained ME besides RK and ZN. These differences in fruit fly-attracting floral scents shown by the sympatric chemotypes of Bu. praetervisum are contrary to that shown by the allopatric chemotypes of Bu. macranthum, demonstrating the versatility in the floral synomone biosynthetic processes. Phylogenetic analysis using chloroplast DNA shows that the Malaysia- and Thailand-chemotypes of Bu. macranthum and Bu. praetervisum belong to the same lineage, although their chemical profiles are distinctly different. This demonstrates that diversification of floral synomone may happen even within a putative orchid species in order to attract a wider community of fruit fly pollinators from different genera to maximize pollination success.

Discrimination of Odors Associated With Conspecific and Heterospecific Frass by Sibling Species Dendroctonus frontalis (Coleoptera: Curculionidae: Scolytinae) and Dendroctonus mesoamericanus (Coleoptera: Curculionidae: Scolytinae).

In the Central American region, the aggressive, sibling bark beetles Dendroctonus frontalis Zimmermann (Coleoptera: Curculionidae: Scolytinae) and Dendroctonus mesoamericanus Armendáriz-Toledano & Sullivan (Coleoptera: Curculionidae: Scolytinae) commonly colonize pines concurrently, and in nature they avoid heterospecific pairing, although it can be produced in the lab. We performed walking arrestment bioassays in the lab to examine the capacity of both sexes of both species to discriminate odors from frass expelled from gallery entrances of either solitary females or conspecific pairs of either species. Males of both species strongly preferred odors of frass from solitary, conspecific females over those of heterospecific females or pairs of either species. Female D. frontalis did not discriminate among these frass categories, whereas female D. mesoamericanus preferred frass of conspecific females. In gas chromatography-electroantennographic detection and gas chromatography-mass spectrometry analyses, we determined that males of both species could sense a nearly identical spectrum of approximately 16 host- and beetle-produced compounds present in frass of females of one or both species. Only two of these compounds, endo-brevicomin and ipsdienol, which were present in frass of female D. mesoamericanus and pairs of either species but absent in frass of solitary D. frontalis females, qualitatively distinguished these categories. Several known attractants and synergists for either species declined in concentration postpairing. Our results complement earlier research and indicate how semiochemical composition and concentration in frass might mediate male discrimination of attack sites of conspecific, unpaired females. Furthermore, our data indicate that semiochemical responses for walking females differ from those of males and between species.

Socially regulated estrogen in an eavesdropping brood parasite

Social regulation of reproductive hormones is a means by which conspecific males and females orchestrate successful reproductive efforts. We investigate whether social cues modify activity within the hypothalamic-pituitary-gonadal (HPG) axis and the specificity of this response in a social parasite that is known to eavesdrop on the communication signals of other species: the brown-headed cowbird (Molothrus ater). Brown-headed cowbirds are obligate brood parasites that do not build nests or care for their own young. Instead, obligate brood parasites leave their eggs in the nest of a host species and therefore must coordinate their breeding attempts with conspecifics as well as potential heterospecific hosts. Here, we explore whether the vocal signals of potential host species can also be used as a social cue that modifies the HPG axis of female brown-headed cowbirds. Results reveal that both conspecific and heterospecific song-exposed females exhibit significantly greater circulating estradiol concentrations as compared to silence-exposed females. While conspecific song induces the greatest elevation in circulating estradiol, there is no significant difference in circulating estradiol levels in females exposed to either conspecific or heterospecific songs. This pattern suggests both song types are effective at evoking a reproductive physiological response. On the other hand, circulating progesterone concentrations did not differ among the song- and silence-exposed groups nor did the size of the female’s ovarian follicles. These results indicate that heterospecific vocal communication signals can effectively be used as a social cue that simultaneously provides necessary information regarding breeding status of hosts and modifies breeding condition of the eavesdropper.

Reproductive isolation between sister species of Iberian pine voles, Microtus duodecimcostatus and M. lusitanicus

Contact zones of recently diverged species provide the ideal opportunity to study the nature of reproductive barriers. The Mediterranean (Microtus duodecimcostatus) and Lusitanian pine voles (M. lusitanicus) are a pair of recently diverged sister species endemic to Western Europe. Recent microsatellite data raised the possibility that hybridisation events, although rare, may still occur in the area of sympatry of both species. Here we evaluated the nature and extent of reproductive isolation between M. duodecimcostatus and M. lusitanicus through a laboratory crossbreeding experiment and two-way mate preference tests on the basis of chemical cues. Crossbreeding of sympatric individuals from the two species was successful and followed Haldane’s rule, revealing hybrid male sterility and reduced fertility of hybrid females. Results from mate preference tests showed males of both pine vole species could discriminate and preferred female conspecifics to heterospecifics or hybrid females on the basis of chemical cues alone. On the contrary, females of both pine vole species did not show a clear preference for conspecific over heterospecific male chemical cues, suggesting females may need additional cues to discriminate between males of the two species. As a whole our results indicate both prezygotic (i.e. species-specific mate recognition systems) and postzygotic barriers (i.e. male hybrid sterility, female reduced fertility and behavioural sterility ― decreased ability to find or attract mates) have evolved, and should make hybridisation of the Iberian pine voles under natural conditions an unlikely event. The role of both species mating preferences and interspecific behavioural interactions in the asymmetric mitochondrial introgression pattern of the Iberian pine voles is discussed.

Functional significance of cuckoo Cuculus canorus calls: responses of conspecifics, hosts and non-hosts.

Male cuckoos Cuculus canorus produce calls that differ in number of syllables depending on environmental conditions and presence of male and female conspecifics. Why different males produce so repeatable calls that vary greatly in duration among males remains an open question. We used playback of cuckoo calls with few or many syllables (hereafter short and long calls), and woodpigeon calls (a control that also produces few or many syllables), predicting that playback of longer cuckoo calls should attract more male cuckoos (if males with such calls are dominant and successfully out-compete other males due to intraspecific competition), and attract more hosts mobbing male cuckoos (cuckoos with such calls and their females attract more hosts because of an increased risk of parasitism). Because cuckoos differentially parasitize hosts away from human habitation, we also tested whether the number of syllables in cuckoo calls differed with distance from buildings. Playback showed significant effects of number of syllables in cuckoo calls, but not woodpigeon Columba palumbus calls, with an additional effect of distance from human habitation decreasing the response to playback. These findings are consistent with the hypothesis that longer cuckoo calls, especially played back near human habitation, attract more conspecifics and hosts than shorter calls. To the best of knowledge this is the first study showing that cuckoo call response modified both other cuckoo individuals, as well as hosts response.

In vivo functional characterisation of pheromone binding protein-1 in the silkmoth, Bombyx mori

Male moths detect sex pheromones emitted by conspecific females with high sensitivity and specificity by the olfactory sensilla on their antennae. Pheromone binding proteins (PBPs) are highly enriched in the sensillum lymph of pheromone sensitive olfactory sensilla and are supposed to contribute to the sensitivity and selectivity of pheromone detection in moths. However, the functional role of PBPs in moth sex pheromone detection in vivo remains obscure. In the silkmoth, Bombyx mori, female moths emit bombykol as a single attractive sex pheromone component along with a small amount of bombykal that negatively modulates the behavioural responses to bombykol. A pair of olfactory receptor neurons, specifically tuned to bombykol or bombykal, co-localise in the trichodeum sensilla, the sensillum lymph of which contains a single PBP, namely, BmPBP1. We analysed the roles of BmPBP1 using BmPBP1-knockout silkmoth lines generated by transcription activator-like effector nuclease-mediated gene targeting. Electroantennogram analysis revealed that the peak response amplitudes of BmPBP1-knockout male antennae to bombykol and bombykal were significantly reduced by a similar percentage when compared with those of the wild-type males. Our results indicate that BmPBP1 plays a crucial role in enhancing the sensitivity, but not the selectivity, of sex pheromone detection in silkmoths.

Field-realistic exposure to the androgenic endocrine disruptor 17β-trenbolone alters ecologically important behaviours in female fish across multiple contexts

The capacity of pharmaceutical pollution to alter behaviour in wildlife is of increasing environmental concern. A major pathway of these pollutants into the environment is the treatment of livestock with hormonal growth promotants (HGPs), which are highly potent veterinary pharmaceuticals that enter aquatic ecosystems via effluent runoff. Hormonal growth promotants are designed to exert biological effects at low doses, can act on physiological pathways that are evolutionarily conserved across taxa, and have been detected in ecosystems worldwide. However, despite being shown to alter key fitness-related processes (e.g., development, reproduction) in various non-target species, relatively little is known about the potential for HGPs to alter ecologically important behaviours, especially across multiple contexts. Here, we investigated the effects of exposure to a field-realistic level of the androgenic HGP metabolite 17β-trenbolone—an endocrine-disrupting chemical that has repeatedly been detected in freshwater systems—on a suite of ecologically important behaviours in wild-caught female eastern mosquitofish (Gambusia holbrooki). First, we found that 17β-trenbolone-exposed fish were more active and exploratory in a novel environment (i.e., maze arena), while boldness (i.e., refuge use) was not significantly affected. Second, when tested for sociability, exposed fish spent less time in close proximity to a shoal of stimulus (i.e., unexposed) conspecific females and were, again, found to be more active. Third, when assayed for foraging behaviour, exposed fish were faster to reach a foraging zone containing prey items (chironomid larvae), quicker to commence feeding, spent more time foraging, and consumed a greater number of prey items, although the effect of exposure on certain foraging behaviours was dependent on fish size. Taken together, these findings highlight the potential for exposure to sub-lethal levels of veterinary pharmaceuticals to alter sensitive behavioural processes in wildlife across multiple contexts, with potential ecological and evolutionary implications for exposed populations.

Identification of Glutamic Acid as a Host Marking Pheromone of the African Fruit Fly Species Ceratitis rosa (Diptera: Tephritidae).

Host marking pheromones (HMPs) deposited by female fruit flies deter other females from overexploiting the same fruit for egg laying. Using a bioassay-guided approach, we identified the HMP of the Natal fruit fly species Ceratitis rosa as glutamic acid, 1, from the aqueous fecal matter extract of ovipositing females by liquid chromatography-quadrupole time-of-flight-mass spectrometry (LC-QTOF-MS). Dual choice oviposition assays showed that both the fecal matter extract and 1 significantly reduced oviposition responses in conspecific females of C. rosa. Glutamic acid levels were 10-20 times higher in fecal matter than in the ovipositor or hemolymph extracts of females. Identification of 1 as a host marking pheromone in females of C. rosa improves our understanding of fruit fly chemical ecology and provides evidence that it could be used as a potential component in the integrated management of this fruit fly species.

Precopulatory mating and postzygotic isolation between two walnut‐infesting species of Rhagoletis from Mexican highlands

AbstractPleistocene glacial and postglacial cycles producing contraction and expansion of temperate habitats have resulted in substantial diversification among several plant and animal taxa of Neararctic origin undergoing periods of isolation and secondary contact in high‐elevation areas of Mexico. One of such groups are walnut‐infesting fruit flies in the genus Rhagoletis (Diptera: Tephritidae), comprised of six recently derived species among which phylogenetic relationships have been difficult to unravel using conventional molecular methods. Here, we examined pre‐ and postzygotic isolation between two genetically similar and morphologically distinct species which are currently parapatric in central Mexico. Local adaptation driven by differences in host plant phenology between Rhagoletis zoqui Bush and Rhagoletis ramosae Hernández‐Ortíz resulted in allochronic isolation. Despite the existence of precopulatory mating isolation, there was a substantial number of hybrid matings in field cages where conspecific and heterospecific males and females were simultaneously released. The bulk of mating activity took place on host fruit. Rhagoletis zoqui females were more reluctant to mate with R. ramosae males than with males of their own species. Distinctive behavioral differences were observed between males during contests, fruit guarding, and approach to conspecifics on fruit. There was also some asymmetric postzygotic isolation, with the hybrid combination of R. zoqui males and R. ramosae females resulting in lower egg hatch than other mating combinations. Results were consistent with those of a phylogenetic study suggesting recent divergence of R. ramosae from Rhagoletis completa Cresson and R. zoqui in the Sierra Madre Oriental and the Mexican Trans Volcanic Belt.

A landscape perspective on rates of multiple paternity and brood parasitism among Greater Prairie-Chickens across Kansas, USA

ABSTRACT Fragmentation and degraded habitat conditions can result in increased competition for critical resources, altered mating systems, and can eventually result in population declines or extinction. We investigated the degree to which habitat degradation and habitat loss impacted the breeding ecology of Greater Prairie-Chickens at 3 study sites across relatively intact grasslands in Kansas, USA. Across all 3 study systems, we found similar rates of multiple mating by females at 14–20% of broods. In addition, we found evidence for facultative nest parasitism of conspecific females. Prairie-chicken females inhabiting more intact and less fragmented landscapes with a higher probability of survival did not engage in parasitic egg laying, whereas ∼17% of females inhabiting a more fragmented and isolated landscape engaged in parasitic egg laying. Parasitic egg layers tended to be older females that parasitized nests of yearling females. Parasitic egg layers only laid parasitically after an initial nesting a...

Number of syllables in cuckoo Cuculus canorus calls: A test using a citizen science project

Recent studies revealed that the call of the common cuckoo Cuculus canorus has more inter-individual than intra-individual variation and that the number of syllables depends on environmental conditions, but also the presence of male and female conspecifics. However, still very little is known about how song varies at a global scale, especially considering the wide distribution of this species across most of Europe and Asia. Xeno-canto.org is a vocalization repository for birdsong. We used xeno-canto.org as a data source for investigating the variables that affect the number of syllables in cuckoo calls at a large spatial scale. At a very broad geographical scale, the number of syllables in cuckoo calls predicted bird species richness. Additionally, female calls were associated with shorter males calls, and there was a positive correlation between the interaction between female calls and the number of host races parasitized by the cuckoo. These findings confirm that intraspecific and interspecific interactions significantly affect the number of syllables in cuckoo calls, and both environmental variables and biotic interactions should be considered in future studies of vocalizations in cuckoos. Last but not least, we demonstrated that a citizen science project is a useful source for ecological studies at large spatial scales.

Gravid females of Cephalcia chuxiongica (Hymenoptera, Pamphiliidae) are attracted to egg-carrying needles of Pinus yunnanensis

CephalciachuxiongicaXiao is one of the most dangerous defoliators ofPinusyunnanensisand other pine species in Yunnan province, resulting in serious losses. Its distinguishing characteristics are the females’ aggregation oviposition and larvae’s aggregation feeding. In order to explore the mechanism of aggregation oviposition in this sawfly, preliminary olfactory bioassay was conducted in laboratory. In in-cage choice tests, on average vast majority gravid females selected the shoots that had been loaded and oviposited by a ‘pioneer’ female. In one-choice tests in laboratory by a Y-tube olfactometer, the gravid females were attracted by the odors of eggs-carrying shoots (PE), shoots with one delivering female and her eggs (PGE), needles’ extract (NE), and fresh eggs’ eluent (EL); the virgin females were attracted by odors of fresh needles (P), PE, PGE, and NE, but repelled by odors of virgin and gravid females. In two-choice tests, the odors were tested in pairs for gravid females. When compared with odors of gravid females (G) or P, gravid females showed significantly more tendency to odors of PE or PGE. When given odors EL vs. NE, gravid females preferred the odors of NE, but they did not make obvious selection between G vs. P, and PE vs. PGE. Based on the results, our conjectures were: (1) Delivery female, as a pioneer, can summon her conspecific gravid females to aggregate in the same pine shoot; (2) Pine needles’ odors were attractive for both the virgin and gravid females; (3) Gravid females could be attracted by odors released by the pioneer gravid females; (4) The olfactory sensation of the females may be changed by mating.

Hybridization and postzygotic isolation promote reinforcement of male mating preferences in a diverse group of fishes with traditional sex roles.

Behavioral isolation is thought to arise early in speciation due to differential sexual and/or natural selection favoring different preferences and traits in different lineages. Instead, behavioral isolation can arise due to reinforcement favoring traits and preferences that prevent maladaptive hybridization. In darters, female preference for male coloration has been hypothesized to drive speciation, because behavioral isolation evolves before F1 inviability. However, as with many long‐lived organisms, the fitness of second‐generation hybrids has not been assessed because raising animals to adulthood in the laboratory is challenging. Of late, reinforcement of male preferences has been implicated in darters because male preference for conspecific females is high in sympatry but absent in allopatry in multiple species pairs. The hypothesis that reinforcement accounts for behavioral isolation in sympatry assumes that hybridization and postzygotic isolation are present. Here, we used genomic and morphological data to demonstrate that hybridization is ongoing between orangethroat and rainbow darters and used hybrids collected from nature to measure postzygotic barriers across two hybrid generations. We observed sex ratio distortion in adult F1s and a dramatic reduction in backcross survival. Our findings indicate that selection to avoid hybridization promotes the evolution of male‐driven behavioral isolation via reinforcement in this system.