Subadult Females Research Articles

A tale of two populations: vital rates of fishers in British Columbia, Canada

AbstractFishers (Pekania pennanti) are a forest‐dependent carnivore of conservation concern in British Columbia, Canada. Ecological, spatial, and genetic evidence suggests that there are 2 distinct populations (Boreal and Columbian) that occur in forests at low to moderate elevations in the boreal and central interior regions of the province. In British Columbia, fishers occur at low densities relative to other parts of their range in North America, are trapped for their fur, and are sensitive to habitat change. Despite these factors, little demographic information exists to assist with management decisions for these populations. We collated and analyzed survival and reproductive data from 100 radio‐tagged fishers from 5 independent studies conducted between 1990 and 2012 in British Columbia: 2 in the Boreal population, and 3 in the Columbian population. We also collated litter size data from 1 den box study and a translocation project of fishers from the Columbian population. Annual survival rates were not significantly different between the populations or between males and females; however, adult survival rates were higher than subadults (0.79 and 0.63, respectively). Subadult females had significantly lower survival rates than other sex or age classes. Reproductive rates were significantly different between the 2 populations (denning rate = 0.54 [Columbian], 0.82 [Boreal]; litter size = 1.7 [Columbian], 2.6 [Boreal]). These differences resulted in net reproductive rates in the Columbian population that were less than half of those in the Boreal population (0.92 kits/reproductive season compared to 2.13, respectively). Population growth rates suggest that the Columbian population may have been declining during the studies, whereas the Boreal population may have been increasing (0.96 compared to 1.20). Consequently, we suggest that focused and intensive habitat and population management for fishers are needed in British Columbia to ensure population sustainability, particularly for the Columbian population.

Effects of urea application on the reproduction of Pardosa pseudoannulata: Field and laboratory studies.

As an important chemical fertilizer, urea can greatly increase crop yields, but it also has negative effects on beneficial arthropods in the agricultural field, such as spiders. Here, we reported that urea application reduced the reproductive performance in Pardosa pseudoannulata, a dominant species of spider in rice fields, which preys on a range of insect pests, based on both field and laboratory studies. In a field test, urea application significantly reduced the egg production of adult and subadult females collected from the urea-treated fields. A laboratory test was set up to further evaluate the impact of urea application on P. pseudoannulata reproduction. In consistent with field test results, the spiders treated by urea for 14d and 28d had lower reproduction ability than their control counterparts, with regard to the mating rate, egg production, and egg hatchability. The transcriptomic sequencing of individuals treated by urea for 28d showed that urea application caused a number of differentially expressed transcripts with several downregulated unigenes related to basic enzymes and several upregulated unigenes involved in stress resistance. The knockdown of a metalloproteinase gene caused a significant decrease in egg production, and the silencing of a carboxylesterase gene significantly reduced both the egg production and egg hatchability. Taken together, the present study found that urea application reduced P. pseudoannulata reproduction ability and the negative impact partially resulted from the downregulation of certain basic enzyme genes. The study provided a fresh view of fertilizers on beneficial arthropods with great potential in the protection of P. pseudoannulata in fields.

POPULATION STATUS AND HABITAT ASSOCIATION OF SWAYNE’S HARTEBEEST (Alcelaphus Buselaphus Swaynei (Sclater, 1892)) IN MAZE NATIONAL PARK, SOUTHWEST ETHIOPIA

We investigated the population status and habitat association of the endemic and emblematic Swayne’s Hartebeest (Alcelaphus buselaphus swaynei) in Maze National Park, Southwest Ethiopia. Line-transect sampling method was used for the population estimation, while habitat association was made based on the abundance of counted individuals in each habitat. Data were analyzed using descriptive statistics and compared with the X2 test. The counted population of Swayne’s Hartebeest in the study period were 1456 and 1492 during wet and dry seasons, respectively showing no seasonal variation. Of these, 31.03% were adult males, 38.53% adult females, 13.95% sub-adult males, 15.96% sub-adult females, and 0.53% young. The number of adult females was higher than in the other age groups followed by adult males in both seasons. Significant differences were observed among age and sex structure during both seasons (wet season: X2= 58.423, df =3, P < 0.05; dry season: X2=534.08, df= 4, P < 0.05). The maximum group size was 36 and the minimum was 1. The ratio of adult males to adult females was 1:1.24 and 1:1.24, sub-adult males to sub-adult females were 1:1.16 and 1:1.12, adult males to sub-adult males was 1:0.36 and 1:0.56, adult females to sub-adult females was 1:0.33 and 1:0.49 in the wet and dry seasons, respectively. The male to female ratio was 1:1.22 and 1:1.19 during wet and dry seasons as well. The population trend among ten years were significantly differed (X2 = 1.71, df= 9, P < 0.05). The Swayne’s Hartebeest was distributed in three habitat types (grassland, riverine forest, and scattered trees) with significant differences (X2=1109.94, df = 3, P < 0.05). The grassland was most preferred by the animal followed by the scattered tree habitat. Managing its habitats is recommended for sustaining the population of the animal

Thoracopelvic Covariation Across Ontogeny in Humans

Clarifying human thoracopelvic covariation patterns can contribute to an understanding of body shape evolution. Previous research has shown that although adult human males and females share a common thoracopelvic covariation pattern, males tend to exhibit mediolaterally wide thoraces and narrow pelves, and females tend to exhibit mediolaterally narrow thoraces and wide pelves (2020 Am J Phys Anthropol 173(3) 514‐534). The current study tests for sex differences in thoracopelvic covariation across ontogeny.I analyzed decedent computed tomography data from the Center for Forensic Imaging at the University of New Mexico with a sample of 44 females and 48 males, aged 0‐21 years. I used SlicerMorph to collect three‐dimensional landmark coordinate data representing thoracic and pelvic shapes as well as R geomorph and Morpho for geometric morphometric analyses. After separate Generalized Procrustes Analyses on the pelvis and thorax, I analyzed thoracopelvic covariation with two‐block partial least squares analysis. To compare covariation magnitudes, I tested effect sizes of sex‐specific two‐block partial least squares. I assessed sex‐specific covariation patterns by projecting the male data into the female two‐block partial least squares analysis and then comparing the slopes of sex‐specific data via major axis regressions and the smatr R package.Results from the two‐block partial least squares analyses indicate significant covariation between the thorax and pelvis in females and males (p=0.001). The first latent variables explain 94.47% and 94.40% of the total covariation in the female and male samples, respectively. In both sexes, as the thorax becomes less pyramidal and more barrel‐shaped with development, the pelvis becomes more anteroposteriorly elongated. The sex‐specific two‐block partial least squares analyses do not exhibit significantly different magnitudes of thoracopelvic covariation. Slope comparison between sexes does not indicate significantly different patterns of thoracopelvic covariation.Previous research suggests that adult thoracopelvic covariation is driven by sex differences. The current study shows that subadult thoracopelvic covariation tracks with growth and development in both sexes, which is expected in the ontogenetic sample. Subadult females and males do not exhibit significantly different magnitudes nor patterns of thoracopelvic covariation. Processes such as sagittal balance of the upper body over the pelvis may influence thoracopelvic covariation.

Flavistic mound-building mouse (Mus spicilegus) in Slovakia

Abstract In this paper are presented two cases of abnormal colouration individuals of Mus spicilegus from northern border of the species’ range. The individuals were caught during long-term research (from 2002 to 2021) of species in autumn-winter seasons in field biotopes on south-eastern Slovakia. The first individual captured on December 2, 2004, was subadult male. The second individual captured on November 11, 2020, was subadult female. Determination by morphological traits and subsequent dissection confirmed that both trapped mice were subadults. According to the findings, the observed individuals meet the criterion of flavism. The dorsal fur was yellow (or beige); the auricle, feet, and tail were light; and coloration on the belly was white. This finding is important not only in terms of colour anomalies, but also in terms of genetics.

Risky business: males choose more receptive adults over safer subadults in a cannibalistic spider.

Understanding factors affecting male mate choice can be important for tracking the dynamics of sexual selection in nature. Male brown widow spiders (Latrodectus geometricus) mate with adult as well as immature (subadult) females. Mating with adults involves costly courtship with a repertoire of signaling behaviors, and typically ends with cannibalism (“self-sacrifice” initiated by male somersault). Mating with subadults involves brief courtship with behavioral repertoire reduced to one component (vibration) and no cannibalism. We examined male mate choice as a function of risks associated with different types of mates and the cues available to courting males. Previous studies showed male preference for adults based on air-borne pheromones, but it was unclear whether that preference is maintained after males reach female’s webs. We show that males prefer adults also based on silk-borne contact cues. To determine which types of cues trigger different courtship components, we swapped adults and subadults between webs. We showed that contact with adult females’ webs triggers two courtship behaviors from the repertoire, with adult female’s bodies triggering additional behaviors. However, vibrational signals occur regardless of the web origin or female developmental stage. We conclude that males recognize subadult females as potential mates, but are more likely to invest in costly courtship behaviors and mating attempts with adults. In our experiments, subadults were less likely to mate than adults. We conclude that mating with adults could be the preferred option for males because of the higher likelihood of copulation, even at the cost of a higher risk of cannibalism.

Survival rates of translocated Gunnison sage‐grouse

AbstractTranslocations have been used as a management tool for the federally threatened Gunnison sage‐grouse (Centrocercus minimus) but have not been rigorously evaluated. We estimated survival of translocated Gunnison sage‐grouse during the first year following release. Survival rates differed among satellite population where grouse were released, and survival was lower during the first 75 days following release than during the remainder of the first year. Age and sex of translocated grouse also influenced survival, but the timing of translocation (spring or fall) was less influential. Survival estimates of translocated Gunnison sage‐grouse were comparable to available estimates for resident Gunnison and greater sage‐grouse (C. urophasianus), suggesting that translocations may be an effective management tool for maintaining isolated populations. However, annual male counts at leks in the release populations were variable and generally declining, indicating that past numbers of Gunnison sage‐grouse translocated to these populations may not be adequate to sustain local populations, if lek counts reflect true population trends. Given that translocation has been identified as a primary management action for the recovery of Gunnison sage‐grouse, we recommend that a long‐term strategy for a translocation program should be developed. The success of a Gunnison sage‐grouse translocation program should be carefully monitored and managers should consider prioritizing captures for translocations with subadult females and males.

Life History Stage and Sex-specific Survival Rates for the Japanese Pond Turtle, Mauremys japonica, in the Foothill Region of Chiba Prefecture, Japan

Life history parameters are essential when we consider appropriate strategy for conservation of wildlife based on population dynamics modelling. In this study, life history stage and sex-specific survival rates of a Japanese pond turtle (Mauremys japonica) population in foothill region were estimated. Life history was divided into three stages based on the age, separately for males and females, estimated by counting the number of annual rings on scutes: juvenile (1–2 years old), young adult (3–4), and adult (>5) in males, and juvenile (1–4), subadult (5–7), and adult (>8) in females. The median annual survival of subadult and adult females was 0.84 (95% credible interval: 0.54–0.99) and 0.94 (0.77–1.00), respectively, and higher than the survival of juvenile females. In contrast, adult survival of males was estimated as 0.79 (0.44–0.99), and it was higher than the survival of young adult and juvenile males. This study showed that the patterns of survivorship of M. japonica coincide with those of other chelonians.

Estimating the demographics of an ocellated lizard (Timon lepidus Daudin, 1802) population through photo identification capture-recapture

This study used photo identification “ capturerecapture” to monitor a population of ocellated lizards (Timon lepidus Daudin, 1802), providing the first data on the demography of this species in the wild. The monitoring was conducted over a period of six years in a valley of the Var River in southeast France, with an average rate of 25 visits per year. This resulted in 1870 exploitable photographs that allowed the identification of 138 different individuals along a 1,600m linear path. For the 114 lizards that were over the age of one, the life history data was analysed with MARK software using the Cormack-Jolly-Seber (CJS) model. This analysis enabled survival estimates – both annual and seasonal (mid-May to end of September versus October to mid-May) – for both sexes. Annual survival appears to be higher in males than in females (0.65 versus 0.48), with a life expectancy of 2.3 years for adult/ subadult males and 1.4 years for adult/ subadult females. During the winter period, monthly survival is close to 1 for both sexes. It is lower during the summer period : 0.92 in males and 0.87 in females. These survival and longevity rates are surprisingly low for a species of this size. However, they can be considered reliable given the high “ recapture” (via photo identification) rates (between 0.465 ± 0.053 and 0.986 ± 0.014 in spring, lower in autumn) and the isolation of the study site.

Determining the Dietary Preferences of Wild Asian Elephants (Elephas maximus) in Taman Negara National Park, Malaysia Based on Sex and Age using trnL DNA Metabarcoding Analysis.

The world's largest terrestrial mammal, Asian elephants, are known to have enormous feeding needs. Several factors such as season, sex, age, and daily activities influence the amount of food required by an individual. Generally, captive elephants have a limited choice of food on a daily basis compared with that of elephants in the wild. Elephants in captivity are fed according to a prepared feeding schedule, whereas wild elephants are free to choose the type of plants that they consume in their natural habitat. In the past, ecological observations have been widely used to determine the diet of wild elephants. However, the molecular approach has never been carried out. In the present study, we aimed to; 1) identify the plant diet of wild Asian elephants in Taman Negara National Park (TNNP) according to their sex and age using high-throughput DNA metabarcoding; and 2) determine the dietary formulation of captive elephants based on the generated plant metabarcoding database. DNA was extracted from 24 individual fecal samples collected using noninvasive sampling techniques from TNNP and the National Elephant Conservation Centre (NECC) Kuala Gandah. Seven pooled samples from male adult, female adult, male subadult, female subadult, male juvenile, female juvenile, and captive elephants were amplified and sequenced targeting the trnL region (50-150 base pairs). The CLC Genomic Workbench and PAST 4.02 software were used for data analysis. In total, 24 orders, 41 families, 233 genera, and 306 species of plants were successfully detected in the diet of the Asian elephants. The most abundant plant genera consumed were Sporobolus (21.88%), Musa (21.48%), and Ficus (10.80%). Plant variation was lower in samples from male elephants than in those from female elephants. The plant species identified were correlated with the nutrient benefits required by elephants. Adults and subadults consumed more plant species than were consumed by juvenile elephants. However, there was no significant difference between ages and sexes. The findings of this study can be used as guidance by the Department of Wildlife and National Parks for the management of captive elephants, especially in NECC Kuala Gandah.

Sex, body size, and boldness shape the seasonal foraging habitat selection in southern elephant seals.

Selecting foraging habitat is a fundamental behavior in the life of organisms as it directly links resource acquisition to fitness. Differences in habitat selection among individuals may arise from several intrinsic and extrinsic factors, and yet, their interaction has been given little attention in the study of wild populations. We combine sex, body size, and boldness to explain individual differences in the seasonal foraging habitat selection of southern elephant seals (Mirounga leonina) from the Kerguelen Archipelago. We hypothesize that habitat selection is linked to the trade‐off between resource acquisition and risk, and that individuals differ in their position along this trade‐off because of differences in reproductive strategies, life stages, and metabolic requirements. Before the post‐molt foraging trip, we used a novel object approach test to quantify the boldness of 28 subadult and adult females and 42 subadult males and equipped them with data loggers to track their movements at sea. Subadult males selected neritic and oceanic habitats, whereas females mostly selected less productive oceanic habitats. Both sexes showed a seasonal shift from Antarctic habitats in the south in the summer to the free of ice subantarctic and subtropical habitats in the north in the winter. Males avoided oceanic habitats and selected more productive neritic and Antarctic habitats with body size mostly in the winter. Bolder males selected northern warmer waters in winter, while shyer ones selected the Kerguelen plateau and southern colder oceanic waters. Bolder females selected the Kerguelen plateau in the summer when prey profitability is assumed to be the highest. This study not only provides new insights into the spatiotemporal foraging ecology of elephant seals in relation to personality but also emphasizes the relevance of combining several intrinsic and extrinsic factors in understanding among‐individual variation in space use essential in wildlife management and conservation.

Two New Cryptic Pristimantis (Anura, Craugastoridae) from the Southern Amazon Basin of Peru with Taxonomic Comments on Pristimantis imitatrix (Duellman, 1978)

Fieldwork in premontane and lowland Amazonian forest (385–1,075 m above sea level) in and around the Amarakaeri Communal Reserve in southeastern Peru led us to describe two new species of the genus Pristimantis. We used integrative evidence from several external morphological characters, morphometric and molecular data, geographic distributions, and multivariate analyses to support the identification of these new species. Pristimantis gagliardi sp. nov. is characterized by lacking a visible tympanic annulus and membrane on skin, having basal webbing between toes, yellow blotches in groin and hidden surfaces of shanks, W-shaped scapular mark, snout subacuminate bearing a very small papilla at tip of snout, and snout–vent length (SVL) = 17.7–21.3 mm in adult males and SVL = 26.7–29.2 mm in females. Pristimantis okmoi sp. nov. is characterized by having a visible tympanic annulus and membrane on skin, basal webbing between toes, yellow blotches in groin and hidden surfaces of shanks, W-shaped scapular mark, snout rounded with small rostral papilla, and SVL = 13.63–17.04 mm in adult males; females unknown. Both species were initially misidentified as P. carvalhoi or P. imitatrix. Additionally, we provide new morphological and phylogenetic data on adult specimens of Pristimantis imitatrix, a rare Amazonian species described based on a single subadult female.

Population genetic structure and dispersal patterns of a cooperative breeding bird in variable environmental conditions

Understanding the effects of environmental conditions in cooperatively breeding species helps reveal the nature of evolutionary forces leading to this type of social system. In particular, environmental variability may affect demographic processes such as mortality and dispersal which can ultimately define the fine-scale genetic structure of cooperatively breeding populations, including direct and indirect fitness opportunities for individuals. We investigated the population genetic structure and dispersal patterns of obligately cooperative white-winged choughs, Corcorax melanorhamphos , exploring within-group relatedness and genetic differentiation among groups sampled over several years of above average rainfall. We compared our results with data from a previous study in the surrounding area, conducted during a drought period. White-winged chough groups showed similar significant genetic differentiation among groups during both drought and nondrought periods. However, we found female-biased dispersal during abundant rainfall years, which contrasts with the previous study conducted during a drought. We also examined differences in genetic structure in the present study, between groups breeding in suburbs versus native woodlands, finding higher within-group relatedness in woodland birds. Dispersal was female biased in both suburban and woodland habitat but subadult females in suburban habitat were more likely to disperse than adult females. We suggest that higher mortality in chough populations (both during a drought and in suburban habitats) led to more breeding opportunities, resulting in higher dispersal, and reflecting lower group stability. Our study suggests ecological conditions are important drivers of social structure in a cooperatively breeding bird, which are likely to be impacted by environmental change, including climate and urbanization. • Chough groups show significant genetic variation in drought and nondrought years. • In nondrought years, in both suburbs and woodland, dispersal is female biased. • Among suburban females, subadults are more likely to disperse than adults. • In drought years dispersal is not sex biased.

Movement and dispersal of a habitat specialist in human-dominated landscapes: a case study of the red panda

BackgroundHabitat specialists living in human-dominated landscapes are likely to be affected by habitat fragmentation and human disturbances more than generalists. But there is a paucity of information on their response to such factors. We examined the effect of these factors on movement patterns of red pandas Ailurus fulgens, a habitat and diet specialist that inhabits the eastern Himalaya.MethodsWe equipped 10 red pandas (six females, four males) with GPS collars and monitored them from September 2019 to March 2020 in Ilam, eastern Nepal. We collected habitat and disturbance data over four seasons. We considered geophysical covariates, anthropogenic factors and habitat fragmentation metrics, and employed linear -mixed models and logistic regression to evaluate the effect of those variables on movement patterns.ResultsThe median daily distance travelled by red pandas was 756 m. Males travelled nearly 1.5 times further than females (605 m). Males and sub-adults travelled more in the mating season while females showed no seasonal variation for their daily distance coverage. Red pandas were relatively more active during dawn and morning than the rest of the day, and they exhibited seasonal variation in distance coverage on the diel cycle. Both males and females appeared to be more active in the cub-rearing season, yet males were more active in the dawn in the birthing season. Two sub-adult females dispersed an average of 21 km starting their dispersal with the onset of the new moon following the winter solstice. The single subadult male did not disperse. Red pandas avoided roads, small-habitat patches and large unsuitable areas between habitat patches. Where connected habitat with high forest cover was scarce the animals moved more directly than when habitat was abundant.ConclusionsOur study indicates that this habitat specialist is vulnerable to human disturbances and habitat fragmentation. Habitat restoration through improving functional connectivity may be necessary to secure the long-term conservation of specialist species in a human-dominated landscape. Regulation of human activities should go in parallel to minimize disturbances during biologically crucial life phases. We recommend habitat zonation to limit human activities and avoid disturbances, especially livestock herding and road construction in core areas.

Sex and age differences in skull size in Myodes glareolus from Slovakia

Abstract The results of a craniometric analysis of the bank vole (Myodes glareolus) were evaluated in this study. Twenty cranial variables were measured and evaluated on 149 skulls (78 males, 71 females) with respect to sex and age. The main aim of this study was to test the sexual dimorphism in skull size. Overall, our results showed that on average, the values for adult and subadult females of M. glareolus were higher than for males. Results presented here thus reveal sexual differences in the measured cranial traits, most expressed for the length of the mandible and the height of the mandible. The effect size was very large for the length of the first upper molar. Comparison of our results with those from other countries confirmed that there are regional differences. These findings highlight the need for craniometric analysis of species also at the regional level.

Polar bear (Ursus maritimus) use of the Cape Bathurst polynya and flaw lead

The Cape Bathurst polynya and flaw lead (CBP) are major, predictable habitat features with ≤15% ice cover in an otherwise ice-covered Beaufort Sea, and thought to provide hunting opportunities for polar bears (Ursus maritimus Phipps, 1774). We assessed 78 adult (female; with and without cubs) and subadult (male and female) polar bears’ use of the CBP from October to June 2007–2014. The CBP was up to 725 km wide in autumn, ice-covered in winter, and <306 km wide in spring. Seventy-nine percent (n = 62) of the bears used the CBP (≥1 location <2.4 km, or one 4 h step length, from the CBP). Use was higher for solitary adult females and subadult males, which travelled faster with low turning angles along wider sections than females with offspring and subadult females. Bears were closest to the CBP during the spring hyperphagia season. Although a wider CBP did not prevent crossing, bears primarily crossed from the coast towards pack ice at locations 53% narrower than areas not crossed. Bears might avoid crossing when it would require a long-distance swim. The CBP affects polar bear ecology by providing hunting habitat and a corridor that could increase prey encounters but may affect movement.

Marginalized Groups of Gelada (Theropithecus gelada) Living in and around the Highly Disturbed Mount Guna Community Conservation Area, Northwest Ethiopia

Gelada (Theropithecus gelada) is the only surviving primate of the genus Theropithecus that is endemic to Ethiopia. It adapted to live in afroalpine and subafroalpine ecosystems of the Ethiopian alpine. Although it is at risk of habitat loss due to agricultural expansion and deforestation, gelada has been classified as a least concern by the IUCN. Gelada has great importance as it represents the Ethiopian national treasure which brings tourists to the country. However, no proper gelada census has been carried out in and around Mount Guna (Mt. Guna). Therefore, the current study aimed to provide an accurate count of gelada individuals living in the study area. Total count along line transects was carried out from January 1–May 30, 2018, to estimate the population of gelada. According to the current result, gelada individuals counted from the entire sites of Mt. Guna were estimated to be 56. Forty-two gelada individuals were counted from outside the protected area, while 14 of them were from the protected area. There was a significant difference between gelada individuals counted from inside and outside the protected areas (P = 0.047). The ratio of age-sex of geladas also computed to be adult males: adult females: subadult males: subadult females: immature is 1 : 3.12 : 0.88 : 1.25 : 0.75 for the total population. Furthermore, five groups of geladas were observed outside the Mt. Guna community conservation area at three sites, while only one group of geladas was identified from the protected area. Based on the current result, we recommend further research to study the population trend, fertility problems, and conservation mechanisms of geladas living within the agricultural land and human-gelada conflicts around Mt. Guna.

Suppression of a Novel Vitellogenesis-Inhibiting Hormone Significantly Increases Ovarian Vitellogenesis in the Black Tiger Shrimp, Penaeus monodon.

In this study, a novel Crustacean Hyperglycemic Hormone-type II gene (CHH-type II) was identified and biologically characterized in a shrimp, Penaeus monodon. Based on its structure and function, this gene was named P. monodon vitellogenesis-inhibiting hormone (PemVIH). The complete cDNA sequence of PemVIH consisted of 1,022 nt with an open reading frame (ORF) of 339 nt encoding a polypeptide of 112 amino acids. It was classified as a member of the CHH-type II family based on conserved cysteine residues, a characteristically positioned glycine residue, and the absence of CHH precursor-related peptide (CPRP) domain. The deduced mature PemVIH shared the highest sequence similarities with giant river prawn sinus gland peptide A. Unlike P. monodon gonad-inhibiting hormone (PemGIH), PemVIH was expressed only in the brain and ventral nerve cord, but not the eyestalks. Whole mount immunofluorescence using a newly generated PemVIH antiserum detected positive signals in neuronal cluster 9/11 and 17 of the brain, commissural ganglion (CoG), and neuronal clusters of ventral nerve cord. The presence of PemVIH-positive neurons in CoG, a part of stomatogastric nervous system, suggested a potential mechanism for crosstalk between nutritional and reproductive signaling. The role of PemVIH in vitellogenesis was evaluated using RNA interference technique. Temporal knockdown of PemVIH in female subadults resulted in a 3-fold increase in ovarian vitellogenin expression, suggesting an inhibitory role of PemVIH in vitellogenesis. This study provided novel insight into the control of vitellogenesis and additional strategies for improving ovarian maturation in P. monodon without the current harmful practice of eyestalk ablation.

Vocal communication in wild chimpanzees: a call rate study.

BackgroundPatterns of vocal communication have implications for species conservation: a change in calling behaviour can, for instance, reflect a disturbed habitat. More importantly, call rate is a parameter that allows conservation planners to convert call density into animal density, when detecting calls with a passive acoustic monitoring system (PAM).MethodsWe investigated chimpanzee (Pan troglodytes schweinfurthii) call rate during the late dry season in the Issa Valley, western Tanzania by conducting focal follows. We examined the socio-ecological factors that influence call production rate of savanna woodland chimpanzees.ResultsWe found that sex, proportion of time spent in a vegetation type, proportion of time spent travelling, time of the day, party size and swollen parous female presence had a significant effect on the call rate. Call rate differed among the different demographic classes with subadult and adult males vocalising twice as often as the subadult and adult females and three times as often as the juveniles.ApplicationsThe use of PAM and recent statistical developments to estimate animal density is promising but relies on our knowing individual call rate, often not available for many species. With the improvement in automatic call detection, we anticipate that PAM will increasingly be broadly applied to primates but also across taxa, for conservation.

Pheromone communication among sexes of the garden cross spider Araneus diadematus

Chemical communication plays a fundamental role in many aspects of an animal’s life from assessing habitat quality to finding mating partners. Behavioural observations show that chemical communication likewise plays an important role in spiders, but the contexts and the substances involved are little explored. Here, we investigate the chemical communication in the garden cross spider Araneus diadematus (Clerck, 1757) between and within the sexes. Using choice trials, we demonstrate that males are attracted to odours of adult females, but not to those of subadult females. Our data further suggest that adult females avoid odours of conspecific adult females, possibly in order to reduce reproductive competition with other females. Cuticle and silk extracts as well as headspace samples of subadult and adult virgin females were analysed via GC–MS. Available candidate compounds for the female sex pheromone were tested via electroantennography on palps (electropalpography) of adult virgin females and on females in behavioural trials. We propose sulcatone (6-methyl-5-hepten-2-one) as a candidate substance for the female volatile pheromone and several long-chained alkanes and alcohols as candidates for contact pheromones. Apart from demonstrating that attraction of males to females depends on the latter’s developmental stage, our study suggests that pheromones can also play an important role between females, an aspect that requires further attention.