Male-specific Iridescent Coloration in the Pipevine Swallowtail (Battus philenor) is Used in Mate Choice by Females but not Sexual Discrimination by Males

We investigated the potential roles in behavioral interactions of sexually dichromatic iridescent blue coloration found on the dorsal hindwing of male Pipevine Swallowtails (Battus philenor). Behavioral experiments in a large enclosure addressed whether male dorsal hindwing coloration mediated sexual recognition by males, female choice of mates, or both. Models presented to males in the enclosure produced responses that show that males discriminate females from other males using chemical but not visual cues. In contrast, ablation of male dorsal iridescence significantly reduced male mating success with virgin females in the enclosure. The results support the hypothesis that male-specific iridescent coloration in this species is a signal that is important for females in assessing either male species identity or quality in intersexual interactions.     

Morphometric changes associated with sex and development in the Malpighian tubules of Aedes aegypti

The Malpighian tubules of Aedes aegypti showed significant differences in their diameters between male and female larvae, male and female pupae, male larvae and male adults and male pupae and male adults. In every case, female values were greater than in males. Measurements of mean nuclear areas of the principal and stellate cells from Malpighian tubules, taken in males and females during development, showed that this parameter in both types of cell was significantly greater in females than in male larvae, pupae and adult stages. In males, significant differences between developmental stages were observed only in comparison with the nuclear area of larvae and adults in the principal cells, but in females, every comparison between stages showed significant differences except between pupae and adults in stellate cells. The frequency distribution of nuclear area values, in development, for male stellate and principal cells, were mostly concentrated in the first seven classes among the 30 classes considered in every stage, while for females, the frequency dropped drastically in the same classes from larvae to pupae and adults, moving to classes of higher values. Considering the importance of Malpighian tubules in insect physiology, the meaning of the differences detected are discussed on the basis of different metabolic levels, between sexes and developmental stages.     

The influence of male presence or absence on the reproductive cycle of celebes black ape females (Macaca nigra)

The effect of male presence on female menstrual cycles was studied in a group of 13 adult female and 3 adult male Celebes black apes (Macaca nigra) living in an outdoor enclosure. When males were absent, all cycling females had longer durations of maximal perineal swelling. Overall cycle length also appeared to be longer when males were absent, but there was no statistically significant increase. The data suggest that male absence results in a longer late follicular stage, perhaps indicating a delay in ovulation. Whereas these findings do imply that male presence may influence female macaque reproductive condition, it is acknowledged that this effect is much weaker than the demonstrated influence of female macaques on male reproductive state.     

Sperm dumping in a haplogyne spider

The present study shows that females of Silhouettella loricatula (Arachnida: Araneae: Oonopidae) manage to process sperm in an unusual and previously unknown way. The male ejaculate consisting of spermatozoa and globular secretion is enclosed in a secretory sac. This may avoid the mixing of sperm from different males and at least severely limit sperm competition. The process of sperm enclosure occurs within the female's sperm storage site (receptaculum) as the ejaculate is not surrounded by a sac inside the male's sperm-transferring organs (palpal bulbs). The secretion forming the sac is produced by glands adjoining the receptaculum. The possibility that globular secretions in the male palpal bulbs partly contribute to the sac cannot be ruled out completely. It is suggested that in S. loricatula , the main function of sperm enclosure in a sac is enabling females to dump the ejaculate of a male. The present study represents the first report on sperm dumping in the family Oonopidae. During five first and three second copulations in the laboratory, the dumping of a sac was observed. One dumped sac was sectioned and contained spermatozoa. Two couples were flash-fixed with liquid nitrogen early during copulation, which revealed the mechanism of the sac dumping. By muscle contractions, the receptaculum is bent backwards and the sac moved into the genital opening. The actual sac dumping occurs most probably in cooperation with the male, which moves his pedipalps rhythmically during the entire copulation. Extensions and furrows on the emboli suggest that they may additionally be used as copulatory courtship devices. The enclosure of sperm from the current male in secretion takes place during or immediately following copulation as all mated females sacrificed after copulation had a new sac containing spermatozoa in the receptaculum. Dumping sperm of a previous male during the next copulation may allow females to bias sperm precedence.     

Challenges of Conserving Blue Bull (<Emphasis Type="Italic">Boselaphus tragocamelus</Emphasis>) Outside the Protected Areas of Nepal

Blue bull, or ‘Nilgai’ (Boselaphus tragocamelus, Pallas, 1766) is the sole member of its genus. It is endemic to the Indian subcontinent and while there are major populations in northern India, there are also smaller populations in Nepal and Pakistan. It is now extinct in Bangladesh. The Nepalese population is sparsely distributed, mostly in the lowland Terai areas, and outside of Nepal’s protected area network. Conflict with local farming communities because of crop damage by nilgai has created conservation challenges and our aim was to document the distribution of nilgai and to explore the conflict between nilgai and the human population in lowland Nepal. Our study focused on the Rupendehi District of Nepal during March to August 2016, where a total of 303 nilgai were counted. The highest population of nilgai was in the community forests and lowest in areas of cultivated land. The distribution pattern of nilgai was clumped, with an average herd size of 5.6 individuals per herd. Crop raiding damage by nilgai created a serious problem in the municipalities, known as village development committees which are located close to potential nilgai habitat. The projected crop yield loss due to nilgai in the study area was NRs (Nepali Rupees) 7,275,507 (US$ 68,633) from March 2015 to March 2016. Vegetable and pulses crops were those most damaged by nilgai, contributing to 14.48 and 10.38% of the total losses, respectively. The local people held mixed perceptions of nilgai. The most negative views were held by people who had experienced some extent of crop loss. Suitable protective measures to minimize crop loss are required such as changing cropping patterns and crop composition, particularly cultivation of medicinal plants are suggested as priorities in highly effective zone. The study noted that there were many threats to nilgai including illegal hunting, poisoning, electric fences and habitat deterioration. Successful nilgai conservation will require further education, gaining support from local people and possibly new crop management techniques.     

Demographic trends in a captive population of red pandas (Ailurus fulgens)

Birth and survivorship data based upon 39 litters born over a ten-year period are examined and discussed. Reproduction in red pandas is characterized by seasonal breeding, small mean litter size, and relatively high survivorship of young, and in general follows a typical “K-selected” life-history strategy. The mean litter size was two, and the sex ratio at birth was approximately 1 male to 1.11 females. Higher male mortality in the early age classes resulted in a sex ratio in favor of females. Mortality was not correlated with age or experience of the mother but was found to be highly positively correlated with an increase in the inbreeding coefficient of the young. There was no significant difference in mortality among the different litter-size classes, and in general mortality decreased with age. Recommendations concerning future management for the study population are given.     

Molecular characterization of coding sequences and analysis of Toll-like receptor 3 mRNA expression in water buffalo (<Emphasis Type="Italic">Bubalus bubalis</Emphasis>) and nilgai (<Emphasis Type="Italic">Boselaphus tragocamelus</Emphasis>)

Toll-like receptor 3 (TLR3), an antiviral innate immunity receptor recognizes double-stranded RNA, preferably of viral origin and induces type I interferon production, which causes maturation of phagocytes and subsequent release of chemical mediators from phagocytes against some viral infections. The present study has characterized TLR3 complementary DNA (cDNA) in buffalo (Bubalus bubalis) and nilgai (Boselaphus tragocamelus). TLR3 coding sequences of both buffalo and nilgai were amplified from cultured dendritic cell cDNA and cloned in pGEMT-easy vector for characterization by restriction endonucleases and nucleotide sequencing. Sequence analysis reveals that 2,715-bp-long TLR3 open reading frame encoding 904 amino acids in buffalo as well as nilgai is similar to that of cattle. Buffalo TLR3 has 98.6 and 97.9% identity at nucleotide level with nilgai and cattle, respectively. Likewise, buffalo TLR3 amino acids share 96.7% identity with cattle and 97.8% with nilgai. Non-synonymous substitutions exceeding synonymous substitutions indicate evolution of this receptor through positive selection among these three ruminant species. Buffalo and nilgai appear to have diverged from a common ancestor in phylogenetic analysis. Predicted protein structures of buffalo and nilgai TLR3 from deduced amino acid sequences indicate that the buffalo and nilgai TLR3 ectodomain may be more efficient in ligand binding than that of cattle. Furthermore, TLR3 messenger RNA expression in tissues as quantified by real-time PCR was found higher in nilgai than buffalo. Electronic supplementary material Supplementary material is available in the online version of this article at and is accessible for authorized users.     

Sex differences in mortality of Japanese macaques: Twenty-one years of data from the Arashiyama West population

Theorists argue that mortality in male mammals should be higher than that of females, and many studies of primates followed across the life course have found this to be the case. This study examines mortality patterns in the rapidly expanding Arashiyama West (Texas) population of Japanese macaques (Macaca fuscata) and finds that males have a significantly lower median survival age (12.2 years) in comparison to females (20.5 years). Males and females are born in equal proportions, but by adulthood there are 2–5 females to every male. Males are at higher risk of falling victim to infectious diseases and human-related causes of death, and they are more likely to “disappear” from the population, which is inferred to result largely from emigration. There are no significant sex differences in the risks of dying from predation, non-infectious illnesses, neonatal defect, or social stress. Males become more susceptible to mortality than females once they reach sexual maturity, and they remain at greater risk than females until their old age. There is no evidence that one sex or the other is at greater risk of dying as infants, or as juveniles. Comparing males of different age classes, adolescent and adult males are more likely to die and to disappear than are juvenile males. These findings support the “high-risk, high-gain” hypothesis that males are mainly lost to the population because of their risk-taking behaviors after sexual maturity, rather than the “fragile male” hypothesis that males are more vulnerable to mortality during the period of growth and development. Am J Phys Anthropol 102:161–175, 1997 © 1997 Wiley-Liss, Inc.     

Aggression with mixed age-sex groups of bolivian squirrel monkeys following single animal introductions and new group formations

The social organization of the Bolivian squirrel monkey (Saimiri boliviensis boliviensis) is thought to be sexually segregated, with males and females forming separate social groups during the nonbreeding season. To investigate the influence of this social order on patterns of aggression, controlled single animal introductions within established groups and establishment of new groups were studied in a systematic manner. Behavioral observations were made using an all-occurrences technique to sample all agonistic interactions. In study I, 4 animals of each age-sex class (adult males and females, juvenile males and females) were introduced one at a time into 4 different social groups composed of 1 adult male and 8 to 10 adult females. Behavioral observations were made prior to and after the introductions. Newly introduced adult males received significantly more contact aggression than other age classes. Only the adult females increased aggression after the introduction of new animals. In study II, new social groups were formed and behavioral observations were made following formation. One group was formed from 7 pairs of familiar females and an unfamiliar adult male. This group had a high frequency of aggression during the first half hour, with contact aggression rising to peaks at 3 and 5 h. The second group consisted of 10 familiar females, 2 pairs of familiar females and an unfamiliar male. There was a significant peak in contact aggression 3 h into the observation.     

Behavior of giant pandas (Ailuropoda melanoleuca) in captive conditions: Gender differences and enclosure effects

The behavior of giant pandas (Ailuropoda melanoleuca) was studied under captive conditions. Both male and female pandas spent similar amounts of time engaged in eating and locomotion. Males performed anogenital‐marking more but rested less than females, which suggests a sexually dimorphic pattern of behavior. Furthermore, females housed in the seminatural environment spent significantly less time engaged in stereotyped behavior than did females housed in the traditional enclosure, indicating that an enclosure environment affects the behavior of giant pandas. These data illustrate the importance of careful management and facility design for captive giant pandas. Zoo Biol 22:77–82, 2003. © 2003 Wiley‐Liss, Inc.     

Elevated testosterone reduces choosiness in female dark-eyed juncos (Junco hyemalis): evidence for a hormonal constraint on sexual selection?

Because testosterone (T) often mediates the expression of attractive displays and ornaments, in the absence of constraints sexual selection should lead to an evolutionary increase in male T levels. One candidate constraint would be a genetic correlation between the sexes that leads to a correlated response in females. If increased T in females were to have deleterious effects on mate choice, the effect of sexual selection on male T would be weakened. Using female dark-eyed juncos (Junco hyemalis), we tested whether experimentally enhancing female T would lead to a decrease in discrimination between two classes of males, one treated with T (T-males) and one control (C-males). The two female treatments (T-implanted and C-females) spent equal amounts of time with both classes of males, but T-treated females failed to show a preference for either male treatment, whereas C-females showed a significant preference, albeit in an unexpected direction (for C-males). T-females were less discriminating than C-females, irrespective of the direction of their preference. To our knowledge, this is the first study to show that circulating hormones can alter female choosiness without reducing sexual motivation. Our results suggest that hormonal correlations between the sexes have the potential to constrain sexual selection on males.     

Mating increases male's interest in other females: a cognitive study in socially monogamous prairie voles (Microtus ochrogaster)

To determine whether socio-sexual interactions with females influence the male prairie vole's cognitive processing, three groups of males were simultaneously exposed to sensory stimuli of a control and a focal female then tested for their behavioral and neuronal responsiveness to the female cues. From the control female, all males received distal cues. From the focal female, the Unmated males received distal cues, the Unmated-Contact males received all cues but did not mate with her, and the Mated-Contact males received all cues and mated with her. Males were tested for their attentiveness to enclosures holding each female and for their memory of the females’ previous location. Males’ brains were then examined to localize activated regions following exposure to the odor of familiar versus unfamiliar focal females. The Mated-Contact males spent more time in the cage of the control female attending to her enclosure than in the cage of the focal female. Exposure to odors of unfamiliar focal females activated the cingulate cortex of Unmated-Contact males. There was a negative correlation between the level of neuronal activation in the retrosplenial cortex of males that were exposed to the odors of a familiar focal female and their attentiveness to the enclosure of the control female. The data suggest that the effect of socio-sexual interactions with a female on males’ cognition depends on the type of sensory signals males receive from females and how individual males perceive those signals.     

Is size assortative mating in Paracalliope fluviatilis (Crustacea: Amphipoda) explained by male–male competition or female choice?

Field and laboratory studies were used to assess: (1) whether size assortative mating occurred in the New Zealand amphipod Paracalliope fluviatilis and (2) hypotheses developed to explain size assortative mating. We found that assortative mating occurred and that larger females carried more eggs, suggesting they may be more valuable as mates. Laboratory experiments were then used to determine whether: (1) male size influenced the size of the female selected (mechanical constraints hypothesis); (2) male size influenced pairing success in the presence of competition (intrasexual selection hypothesis); (3) take‐overs of females occurred and whether large males were more successful (intrasexual selection hypothesis); (4) guard duration varied relative to male and female size (guard duration hypothesis); and (5) females had control over pairing success and guard duration (intersexual selection hypothesis). Although there was evidence to suggest the existence of intrasexual competition for mates (i.e. both small and large males preferred large females), there was no evidence of overt competition (i.e. takeovers of paired females). There was also no difference with respect to how long small and large males guarded females, but large females were guarded longer by both male size classes. Females handicapped by having their mobility reduced were guarded for the same duration as control females but males were more likely to pair with handicapped females, suggesting that they were easier to amplex. Given the lack of evidence for direct male–male competition or female choice, we suggest that assortative mating may be the result of: (1) indirect competition (e.g. in situ large males may be better able to access and amplex the largest females) or (2) female resistance to small males in combination with higher costs that small males may incur in securing large females. © 2007 The Linnean Society of London, Biological Journal of the Linnean Society, 2007, 92 , 173–181.     

Effect of male and female multiple mating on the fecundity, fertility, and longevity of diamondback moth, Plutella xylostella (L.)

Abstract:  The effect of diamondback moth (DBM), Plutella xylostella (Lep., Plutellidae) male and female multiple mating on fecundity, fertility, and longevity was studied. Males could mate for five times with virgin females during scotophase. The successful copulation rates, fecundity of female, and longevity of both females and males decreased when male mating times increased, whereas copulation duration increased. Correlation coefficient between copulation duration and male mating times was significant ( r  = 0.7358, P = 0.0001, spearman rank-order correlation). There were linear relationships between mating history of males and longevities of males and females, and regression relationships between them were significant. Mated females had similar daily reproductive pattern, which laid the most eggs on the first day after mating in spite of their mates' mating history. Virgin females laid some infertile eggs before they died. Most of the females mated once during their lifespan but 19.9% of females mated twice when one female kept with one male during scotophase. There were no significant differences in the fecundity, fertility and longevity between the single- and twice-mated females. Correlation coefficient between copulation duration and female mating times was not significant ( r  = 0.0860, P = 0.8575). Results suggested that DBM females may be monandrous. Multiple mating did not increase male or female mating fitness.     

Fish predation on Eudiaptomus gracilis in relation to clutch size,body size,and sex: a field experiment

An enclosure experiment was performed to test for direct predationeffects on fecundity and adult body size of the copepod Eudiaptomus gracilis in the field. By introducing a high densityof fish (15 underyearling roach, Rutilus rutilus, per 350litre enclosure) and documenting the short-term effects on traitsin a rapidly decreasing prey population, responses to changes inthe phytoplankton community were minimized. After 68 hours ofpredation, clutch size and frequency of females carrying eggs weresignificantly lower in fish enclosures. Female density was moreaffected than male density. Predation selected against large bodysize in both sexes but less so in females, leading to an increasedsexual size dimorphism. The results agree with predictions based onprey selectivity in fish. Predation risk should increase withclutch size and body size since these traits increase theconspicuousness of prey. The size of the highly visible egg-clutchmay be more important than body size. Female body size wasuncorrelated to clutch size, which may explain the weaker sizeeffect among females and the changed sexual sizedimorphism.     

Social Behaviour and Cooperative Breeding in Arctic Foxes,Alopex lagopus (L.), in a Semi-natural Environment

Most canid species show cooperative breeding at least occasionally. The helper-at-the-den system, when extra adults serve as helpers by feeding and guarding the cubs of an alpha pair, has been observed but not studied in any detail in wild Arctic foxes (Alopex lagopus). During a 3-months study of arctic foxes in two enclosures of 4 ha each, we measured the social behaviour during the reproductive season. Older foxes dominated younger ones and males dominated females of the same age. A litter with one surviving cub was born in one enclosure. The alpha male increased his rate of urine marking and barking and fed the alpha female both before and after the birth of the litter. However, about 10 days after the birth, the alpha female died. The cub was fed by his putative father, his sister and his brother (both one year old). The one year old female increased her rate of territorial defence, measured as urine marking and barking, when the mother died. The subordinate females were probably suppressed from breeding by the high aggression levels and territorial defence of the dominant females in each enclosure. The dominant female in the second enclosure came into heat after the death of the alpha female (her mother) in the first enclosure. These changes in behaviour can probably be explained by sexual inhibition by the alpha female while she was present. The significance of territorial defence and dominance, inbreeding avoidance, sexual suppression and evolution of helping behaviour are discussed.     

Ploughing behaviour of Babyrousa babyrussa, (Suidae, Mammalia) suggests a scent-marking function

A unique form of behaviour,'ploughing behaviour', was studied in experiments carried out on 13 babirusa, three adult males, two sub-adult males, five adult females and three sub-adult females. Ploughing behaviour was observed when individual animals were introduced singly into empty sand-filled enclosures at Antwerp Zoo. The animal put its snout into the sand to such a depth that the sand was just in front of its eyes, whereupon it knelt and slid forward on to its chest. The head and chest of the animal were thereby pushed forward through the sand and canted left and right alternately. Ploughing behaviour was almost exclusively performed by adult males, the periods of longest duration being seen either in the enclosure of another male or in a freshly cleaned enclosure. The copious amounts of saliva which were produced as foam at the sides of the mouth prior to ploughing had disappeared by the end of this activity. This supports the idea that ploughing by the babirusa has a scent-marking function. The adult female did not show ploughing behaviour.     

Sex Differences in Feeding,Height, and Space Use in Hapalemur griseus

I investigated sex differences in feeding ecology in a wild group of Hapalemur griseus, gray bamboo lemur, in southeastern Madagascar. Males and females differed in daily dietary diversity, height use while feeding, and spatial position within the group. Based on all-occurrences of feeding bouts and 15-min point samples, the adult female had significantly higher daily dietary diversity indices than those of males. The female also fed at significantly lower heights than the males did. There are also significant differences between age classes with the subadult male exhibiting the lowest dietary diversity and feeding at the greatest heights. During feeding, the female stayed in closest proximity to both juveniles, whereas adult males were peripheral. In contrast, the males moved closer in proximity to the female when resting and traveling. These sex differences could be explained 1) by the metabolic cost of reproduction for females, 2) as strategies to mitigate the cost of feeding competition between males and females, 3) by male role performance as a predator detector, and 4) by different social priorities of males and females.     

Activity budgets and use of enclosed space by wild boars (Sus scrofa) in captivity

This research was conducted on a captive group of eight wild boars: Four wildborn adults (one male and three females) and four piglets (one male and three females), born in captivity two months before the beginning of the study. They were housed in the Rome Zoo in a 1,000 sq m enclosure furnished with trees, mud pools, a water basin, and two small barns. Data on eight behavioral states (sleeping, resting, rooting, eating, walking, standing, scratching, and nursing) were collected by instantaneous sampling at 10-minute intervals. The spatial location of each subject was also noted, as well as closeness to conspecifics. Results showed that adults and piglets differed in their activity budgets. Activity patterns showed a significant correlation with the mean temperatures. Furthermore, there was a significant difference in the use of the exhibit areas between adults and piglets. This study suggests a social structure in which the core is constituted by females and their yearlings. The nonbreeding female has a more marginal position than the breeding ones. Finally, the male tends to be even more peripheral and solitary. Our results are partly consistent with the data obtained in studies on free-ranging wild boars (Mauget, 1980; Dardaillon, 1984).     

Black rhinoceros (Diceros bicornis) in U.S. zoos: II. behavior,breeding success,and mortality in relation to housing facilities

The captive population of black rhinoceros (Diceros bicornis) is not self‐sustaining. The reasons for suboptimal reproduction and high mortality need to be investigated. This can only be achieved by cross‐institutional analyses of environments, behavior, and performance. In this study, we collected data on 23 zoos with black rhinoceros to compare zoo environments with reproductive success, mortality, and behavior. Institutional variation was characterized by enclosure area, percentage of walls around enclosure perimeter, percentage of public access along enclosure perimeter, climate, noise level, number of years zoo has maintained black rhinoceros, frequency of chlorine use, and number of male and female black rhinoceros at a zoo simultaneously. Birth and death rates for each institution were calculated from studbook records. We found that the breeding success of a zoo since 1973 correlated positively with enclosure area, and zoos with two or more females had a lower reproductive rate than zoos with only one female. Females residing during their pre‐reproductive years at a zoo with another reproductive female gave birth for the first time on average 3 years later than sole females. Mortality since 1973 correlated positively with percentage of public access. In Part I, we developed behavior profiles of 29.31 individual black rhinoceros from keeper ratings. Scores for males on the behavior trait Fear also correlated positively to percentage of public access, and we suggest that this aspect of black rhinoceros exhibits is a stressor for this species, especially the males. We found that different aspects of captive environments are associated with male and female black rhinoceros behavior. Male scores on the behavior trait dominant were higher in smaller enclosures, and female scores for a group of behaviors suggesting agitation (chasing/stereotypy/mouthing) were positively correlated with percentage of walls in their enclosure. These two behavior traits were found in Part I to be negatively correlated with the breeding success of an individual male or female. We re‐surveyed the behavior and husbandry of 29 black rhinoceros pairs in zoos 2 years after the original data were collected. The re‐survey confirmed that compatible black rhinoceros pairs are those with assertive females and submissive males, and that enclosure area and a low percentage of concrete walls around the enclosure are positive predictors of a pair's reproductive success. We conclude that temperament traits of individuals and characteristics of their captive environments both have an impact on a pair's breeding success. Our study demonstrates that cross‐institutional comparisons of zoo facilities, when integrated with behavioral assessments of individual animals, are a valuable tool for investigating potential causes of poor reproduction and well‐being in zoo animals. Zoo Biol 18:35–52, 1999. © 1999 Wiley‐Liss, Inc.