Differences In Responses Of Males Research Articles

Region-Specific Variation in the Electrophysiological Responses of Spodoptera frugiperda (Lepidoptera: Noctuidae) to Synthetic Sex Pheromone Compounds.

The fall armyworm, Spodoptera frugiperda (J.E. Smith), is a global pest that feeds on > 350 plant species and causes major yield loses. Variation in the responses of S. frugiperda males to female sex pheromone compounds affects the detection, monitoring and management of the pest. We determined geographic variation in the responses of S. frugiperda males to four different doses of synthetic sex pheromone compounds using a gas chromatography-electroantennogram detector (GC-EAD). Furthermore, we disentangled regional populations into C- and R- mitotypes via molecular analysis of the cytochrome oxidase I gene, and measured their responses to the compounds. When comparing responses of males from Florida, Benin, Nigeria and Kenya, we found some regional differences in the responses of S. frugiperda males to the major compound, Z9-14:OAc and minor component Z9-12:OAc. However, we found no differences in male responses between the different African countries. All males showed significantly higher antennal responses to Z7-12:OAc than to E7-12:OAc. When comparing the mitotypes, we found that Florida R-type males showed higher responses to Z9-14:OAc, Z7-12:OAc and Z9-12:OAc than Benin R-type males, while C-type males from both regions responded equally to Z7-12:OAc. In addition, Florida R-type males showed higher responses to E7-12:OAc than Florida C-type males. Our study thus shows some differential physiological responses of S. frugiperda males towards the known sex pheromone compounds, including E7-12:OAc, but mostly in the different mitotypes. How these differences translate to field trap catches remains to be determined.

Sex-Dependent Phenological Plasticity in an Arctic Hibernator.

Hibernation provides a means of escaping the metabolic challenges associated with seasonality, yet the ability of mammals to prolong or reenter seasonal dormancy in response to extreme weather events is unclear. Here, we show that Arctic ground squirrels in northern Alaska exhibited sex-dependent plasticity in the physiology and phenology of hibernation in response to a series of late spring snowstorms in 2013 that resulted in the latest snowmelt on record. Females and nonreproductive males responded to the >1-month delay in snowmelt by extending heterothermy or reentering hibernation after several days of euthermy, leading to a >2-week delay in reproduction compared to surrounding years. In contrast, reproductive males neither extended nor reentered hibernation, likely because seasonal gonadal growth and development and subsequent testosterone release prevents a return to torpor. Our findings reveal intriguing differences in responses of males and females to climatic stressors, which can generate a phenological mismatch between the sexes.

Gender differences in responses in Gammarus pulex exposed to BDE-47: A gel-free proteomic approach

Very few ecotoxicological studies have considered differences in toxic effects on male and female organisms. Here, we investigated protein expression differences in caeca of Gammarus pulex males and females under control conditions (unexposed) and after 96h exposure to BDE-47. Using gel-free proteomic analysis, we have identified 45 proteins, of which 25 were significantly differently expressed according to sex and/or BDE-47 exposure. These proteins were involved in several biological processes such as energy metabolism, chaperone proteins, or transcription/translation. In unexposed amphipods, 11 proteins were significantly over-expressed in females, and 6 proteins were over-expressed in males. Under BDE-47 stress, 7 proteins were differently impacted according to sex. For example, catalase was over-expressed in exposed females and under-expressed in exposed males, as compared to respective controls. Conversely, proteins involved in energy metabolism were up-regulated in males and down-regulated in females.Our proteomic study showed differences in responses of males and females to BDE-47 exposure, emphasizing that sex is a confounding factor in ecotoxicological assessment. However, due to the limited information existing in databases on Gammarids, it was difficult to define a BDE-47 mechanism of action. The gel-free proteomic seems to be a promising method to develop in future ecotoxicological studies and thus, to improve our understanding of the mechanism of action of xenobiotics.

Contact pheromones mediate male preference in black widow spiders: avoidance of hungry sexual cannibals?

Males often exercise mate choice when mating frequency is constrained, costs of choice are low and variation in female quality and/or expected paternity can be reliably detected. Across invertebrates, males use sex pheromones to discern female mating status, but there are few demonstrations that information about expected fecundity (‘quality’) is encoded in pheromones alone. Here we examine whether females' sex pheromones allow males to detect differences in female food intake and mass in two species of widow spiders (Latrodectus hesperus and Latrodectus hasselti) in which chemicals are deposited by females in silk. Recent work shows that male L. hesperus prefer well-fed females, and that these females produce more silk than hungry females. Thus, changes in diet could be mechanistically linked to changes in silk-bound pheromonal signals. We show that unmated females of both species lose more than half of their mass when food is withheld, and silk production is reduced by 48% (L. hesperus) to 67% (L. hasselti). Males had a significant sexual response to pheromones extracted from the females' silk in both species, although this response was not directly correlated with silk or female mass. In L. hesperus, but not in L. hasselti, males were less responsive to sex pheromones from food-deprived females compared to well-fed females. While females on good diets provide the benefit of higher fecundity in both species, the risk of being cannibalized by hungry females during courtship exists only in L. hesperus. We conclude that sex pheromones alone can provide information about recent female feeding history, possibly reducing the costs of males expressing choice in the field. The species difference in male response also suggests that male preferences in these spiders may depend less on the benefit of seeking a highly fecund female and more on avoiding the cost of risky mating attempts with a likely cannibal.

Population differences in male responses to chemical mating cues in the white-spotted longicorn beetle, Anoplophora malasiaca

Adult Anoplophora malasiaca beetles were collected from field populations inhabiting three different host plants: Citrus, Salix and Vaccinium. Male orientation responses towards odours of wounded branches of each host plant were examined. Males of all three populations were attracted most frequently to odours of their original hosts, indicating that male orientation behaviour was induced by the odours of the plants from which they were originally collected. We also observed the mating responses of the males to elytra extracts from young and mature females of the three populations and chemically analysed those extracts. Citrus males were highly responsive to female extracts, regardless of origin. Salix males were less reactive than Citrus males, but responded moderately to female extracts of all populations. Vaccinium males were never attracted to Citrus female extracts and responded more to extracts from mature Vaccinium and Salix females, indicating that males might distinguish female origin and maturity. All eight hydrocarbons, four ketones, and three lactones that were previously identified as female contact sex pheromones were found in the extracts of three populations and both ages. Higher amounts of lactones on mature females likely caused greater male responses. These results suggested that males would be more likely to approach a female feeding on the same host plant and subsequently recognise her sexual maturity based on the profile of contact sex pheromones on her elytra.

Acute footshock-stress increases spatial learning–memory and correlates to increased hippocampal BDNF and VEGF and cell numbers in adolescent male and female rats

It is well known that the acute-stress enhances cognitive functions in adults, but is not known in adolescents. The purpose of this study is to investigate the effects of low and high intensities of acute-stress on hippocampus and spatial memory in the adolescent male and female rats. Thirty-eight days aged rats were subjected to 0.2 and 1.6mA intensity of footshock-stress for 20min. Spatial memory performance was assessed in the Morris water maze. Learning had been positively affected in stress groups. Neuron density in the CA1 hippocampal region and the gyrus dentatus as well as VEGF and BDNF levels of hippocampus increased in all stress groups. In females, learning process and BDNF levels increased in low-intensity-stress group than high-intensity-stress group. There was no difference in hippocampal apoptosis among groups.We conclude that adolescent hippocampus is affected positively from acute-stress; however, while there is no difference in male response with respect to intensity of stress, females are affected more positively from low-intensity of stress.

Reidentification of pheromone composition of Sparganothis sulfureana (Clemens) and evidence of geographic variation in male responses from two US states

GC-EAD analyses of pheromone gland extracts of calling female Sparganothis sulfureana revealed at least 6 compounds that consistently elicited antennal responses from male antennae. In addition to the major pheromone compound, ( E)-11-tetradecenyl acetate ( E11–14:OAc), which was previously reported, the other compounds were found to be ( E)-9-dodecenyl acetate ( E9–12:OAc), ( Z)-9-dodecenyl acetate ( Z9–12:OAc), ( Z)-9-tetradecenyl acetate ( Z9–14:OAc), ( Z)-11-tetradecenyl acetate ( Z11–14:OAc), and ( E)-11-tetradecenol ( E11–14:OH). Tetradecyl acetate, hexadecyl acetate and hexadecenyl acetates were also present in the extracts, but elicited no EAG response from male antennae. Wind tunnel tests demonstrated that males from New Jersey responded equally well to a blend containing five pheromone components in relative to the pheromone glands of calling females. Different male-response profiles from field-trapping tests conducted in the states of Wisconsin and New Jersey were observed, respectively. Significantly higher numbers of male S. sulfureana were caught in New Jersey in traps baited with the binary blend of E11–14:OAc (30 μg) with 1% of Z11–14:OAc, but males from Wisconsin responded equally well to traps containing blends of E11–14:OAc with 0–10% of Z11–14:OAc. The addition of more than 10% of Z11–14:OAc to the primary pheromone compound reduced male captures significantly in both states. Male catches were doubled by adding E9–12:OAc and E11–14:OH to the most attractive binary blend in both states. The trapping test with caged live virgin female moths showed that males in Wisconsin preferred females from the local population than those from New Jersey. The differences in male responses observed may indicate the existence of pheromone polymorphism in this species.

Effects of male body size on mating activity and female mate refusal in the yellow-spotted longicorn beetle, Psacothea hilaris (Pascoe) (Coleoptera: Cerambycidae): Are small males inferior in mating?

In the yellow-spotted longicorn beetle, Psacothea hilaris (Pascoe), variation in body size is conspicuous, especially in males. Size-related difference in male response to females and dummies treated with female extract were examined in the laboratory. Smaller males more frequently located and mounted females than did larger males when introduced to females. Smaller males responded to dummies treated with lower doses of female extract. This result indicates that small males were more sensitive to female sex pheromone and more active in their mating search and pre-copulatory behavior. However, females preferred large males to small ones. They displayed mate refusal behavior to small males much more frequently than to large males. A higher sensitivity to sex pheromone and subsequently higher copulatory activity in small males may compensate for the disadvantage of lower female choice. This hypothesis was supported by a field investigation: body size distributions were not significantly different between mounting males and solitary males.

Navigation of Lutzomyia longipalpis (Diptera: Psychodidae) under dusk or starlight conditions.

The responses of male and female Lutzomyia longipalpis (Lutz & Neiva) to different wavelengths of light was tested by presenting the sandflies with two light sources simultaneously, a series of test wavelengths between 350-670 nm and a 400 nm control. To test whether L. longipalpis could discriminate between the test and control, three sets of experiments were carried out in which the test wavelengths were presented at higher, equivalent or lower intensity than the control. In all three experiments, ultra-violet (350 nm) and blue-green-yellow (490-546 nm) light was more attractive to L. longipalpis than the control wavelength. However, at low intensity, UV was less attractive, than equivalent or higher intensity UV light. At intensities equivalent to or higher than the control wavelength, ultra-violet light was more attractive than blue-green. Furthermore, at low intensity, green-yellow (546 nm) light was more attractive to males whereas blue-green (490 nm) was more attractive to females. Blue-violet (400 nm) and orange-red (600-670 nm) light were least attractive in all three sets of experiments. Response function experiments indicated that the responses were dependent on both intensity and wavelength and that therefore more than one photoreceptor must be involved in the response. The results indicated that L. longipalpis can discriminate between different wavelengths at different intensities and thus have true colour vision. It also suggests that L. longipalpis may be able to navigate at dusk or under moonlight or starlight conditions using light in the blue-green-yellow part of the spectrum. The difference in response of males and females to light in this region is interesting and may indicate the different ecology of the sexes at night. Overall, these results may have important implications for sandfly trap design.

The Response of Male Redwings Turdus iliacus to Playback of Conspecific Songs with or without the Terminating Twitter

The song of male Redwings can be divided into two parts, an introductory section and a terminating section (twitter). A previous study found that the introductory section was sung throughout the breeding season, whereas the terminating section, or twitter, was sung more often and was of longer duration early in the breeding season. I carried out playback experiments to test whether the two parts of the song might communicate different motivational information in territorial defence. There was no difference in response of males to the two playback stimuli, introduction alone or complete song (introduction and twitter), early in the season. In response to the playback songs, however, the males primarily sang this section, suggesting that it contains a message to competitors. Later in the season the males responded more to complete songs than to the introduction alone. I suggest that the whole song may be used in territorial defence but that the terminating section may signal a state of increased aggression. The lack of difference in response early in the season might result from a generally higher aggressive level at this time.

An experimental comparison of selection methods

Five methods of selection each in five replicates were examined for single-generation response in high and low 21-day pupal weight of Tribolium castaneum. The methods of selection tested were individual (ID), dam family or full (DF), sire family or half-sib (SF), progeny test (PT), and index (IX). A selection intensity, involving as parents the top 25% of the individuals on any specific phenotypic scale, was applied throughout the experiment. Each replicate included a contemporaneous, randomly mated control line. Responses attained with each method were compared with predicted gains and with results observed for other methods. Differences in responses of males and females were also assessed. Response to selection was markedly asymmetrical with greater gains observed in the downward direction. In the lines selected for low pupal weight, males and females were found to respond similarly and actual responses did not differ from those predicted. Ranking of methods by responses obtained for downward selection yielded the order IX > ID > PT > DF > SF. Selection for high pupal weight yielded differences in responses of males and females and the observed responses were significantly less than those predicted in all cases except that of PT-selected females. Observed responses for males were ordered as IX > ID > PT > DF > SF, while those for females were PT > IX > DF > SF > ID. When the data from both sexes were combined, the order of responses was PT > IX > DF > ID > SF.Key words: asymmetrical response, selection, Tribolium, pupal weight.

The influence of race and gender on perceptions of community impact

Since 1968, research in public transportation planning has included an increasing number of analyses of the perceptions and attitudes of people who use and live in proximity to the systems (Nash and Hille 1968, McMillan et al. 1969, Wachs 1976). The results of the study reported here suggest that race and gender may explain more about attitudes toward the community impact of a transit system than do the levels of user satisfaction with the system. The implication for future research in this area is that surveys employing “satisfaction” and “importance” as indicators may not be using appropriate indices of evaluation. This study reports the results of a 1980 attitude survey of the perceptions of black and white men and women living within a two-block corridor along the Metropolitan Atlanta Rapid Transit Authority (MARTA) east line in Atlanta, Georgia. The research supports the Atlanta Regional Commission (ARC) Transit Impact Monitoring Program (TIMP). The survey used a stratified random sample technique to identify 100 households in which in-home interviews were subsequently conducted. A further stratified sampling procedure designated the gender and age of persons to be interviewed. The analysis included the isolation of responses by gender and race and used the chi-square statistic at the 0.05 significance level. The results identity differences in responses of males and females, blacks and whites.

Extraction and Bioassay of, and Effect of Solvents on, the Sex Pheromone of the Yellow Scale1, 2

A sex pheromone of the female yellow scale, Aonidiella citrina (Coquillett) (Homoptera: Diaspididae), obtained by Soxhlet extraction with diethyl ether of homogenized virgin females or by cold trap condensate liquid:liquid extraction and by steam distillation in diethyl ether, caused attracted males to display the same copulatory behavior as they did toward live mature virgin females. However, the cold trap condensate extractions lured the most males and the steam distillation extracted more total sex pheromore than liquid:liquid extraction. Sex pheromone volatilized more uniformly from chloroform than from diethyl ether; however, the difference in male response to pheromone in the 2 solvents was not consistently significant.