Ectoparasite Load Research Articles

Prevalence and seasonal variation of ectoparasite load in free-range chicken of Kashmir valley

A faunistical study of ectoparasites was carried out for a period of two years from January 2005 to December 2006 in rural free-range chicken purchased from different areas of Kashmir valley. Screening of a total of 478 birds revealed only lice infestation with an overall prevalence of about 100% and 97.69% birds harboring multiple species. The prevalence for various species of lice, during winter, spring, summer, autumn and overall prevalence respectively, was 90.32%, 99.14%, 100%, 98.34% and 96.86% for Lipeurus caponis; 33.87%, 48.71%, 57.75%, 39.66% and 44.76% for Goniodes gigas; 29.83%, 32.47%, 45.68%, 32.23% and 34.93% for Menopon gallinae; 28.22%, 32.47%, 39.65%, 32.23% and 33.05% for Menacanthus cornutus; 16.12%, 19.65%, 25%, 18.18% and 19.66% for Goniocotes gallinae and 6.45%, 12.82%, 13.79%, 4.95% and 9.41% for Eomenacanthus stramineus. The seasonal influence on nature and intensity of infestation was evident.

Manipulating grooming by decreasing ectoparasite load causes unpredicted changes in antagonism.

It is thought that allogrooming is practised strategically in order to establish, maintain and reinforce social bonds between group members, exchanging one altruistic behaviour for a different form of reciprocated benefit at a later date. Correlational evidence supports this, but evidence of causality is lacking. We reduced parasite loads in eight meerkat Suricata suricatta groups, generating a substantial decrease in grooming. Contrary to the predictions, overall antagonism did not increase. However, within group networks, grooming increased towards individuals who increased their antagonism. This was restricted to antagonism focused on social position, rather than access to physical resources. The treatment also increased an alternative placatory behaviour: unprompted submissions. Following treatment, individuals performed higher rates of guarding and marking behaviours, suggesting that they were stressed. A reduction in opportunity to mediate stress through grooming may explain local rises in antagonism and corresponding increases in placatory behaviours. We suggest that meerkats use allogrooming (and submissions) as a facultative response to antagonism, rather than a pre-emptive strategy to avert it by establishing a network of associations, as has been suggested for primates.

Different habitats, different pressures? Analysis of escape behaviour and ectoparasite load in Podarcis sicula (Lacertidae) populations in different agricultural habitats

AbstractHuman agricultural activities can deeply alter the environment thus provoking major impacts on a variety of organisms. Agricultural habitats however can be very different from one another in terms of habitat structure and management intensity, presenting varying pressures and/or benefits for different species. Agro-ecosystems can have opposing effects on reptiles and in some circumstances the presence of a species can even been enhanced by agricultural practices. We focused our study on Podarcis sicula, a relatively widespread lacertid lizard commonly present in agro-environments in Italy. We examined escape behaviour, caudal autotomy rates and ectoparasite load (tick infestation) in populations living in two different land uses, olive tree plantations and vineyards. All three aspects seemed to be deeply influenced by habitat structure. Predation pressure, as evaluated by tail break frequency, was lower in olive tree plantations, the most structurally complex habitats. In this type of habitat lizard escape behaviour was characterised by a clear preference for olive trees as refuges: individuals ran farther distances on average to reach the trees and hid inside them for a relatively long time. In vineyards, on the contrary, a less clear escape strategy was observed, showing a use of more temporary refuges. Also tick (Ixodes ricinus) infestation differed among land uses, being higher in olive tree plantations, probably in relation to vegetation cover features. Differences were found also between managements (with a higher tick load in traditional cultivations) and sexes, with males being more parasitized.

Ectoparasite Presence, Density, And Unit Load In Relation To Tent-roosting Behavior Of Neotropical Bats

Behavioral defenses have evolved in response to the negative effects caused by ectoparasitism. Within neotropical bats, roosting behaviors have been studied as a possible reaction to the presence of parasitic bat flies and mites. Tent-making, the process of actively constructing protective roosts in foliage, was studied in order to assess its specific impact on ectoparasitism. Bats that exclusively utilized tents were predicted to suffer a lower level of ectoparasitism as their roosting behavior can disrupt ectoparasite lifecycles. I captured different bat species, categorized as either tent-roosting or non-tent-roosting, at several sites in Costa Rica, including Monteverde, San Luis and Peñas Blancas. All ectoparasites were collected with forceps and ultimately used to calculate presence, density, and unit load. After analysis, the bat species grouped as tent-makers, Artibeus toltecus and Platyrrhinus helleri, contained significantly lower levels of ectoparasite presence, density, and load in comparison with the species of bats that do not exclusively use tent roosts. These results, though suggestive, are derived from a relatively small sample of tent-making bats and can be strengthened by further replication on a larger scale.

Seasonal and spatial dynamics of ectoparasite infestation of a threatened reptile, the tuatara (Sphenodon punctatus)

The conservation of threatened vertebrate species and their threatened parasites requires an understanding of the factors influencing their distribution and dynamics. This is particularly important for species maintained in conservation reserves at high densities, where increased contact among hosts could lead to increased rates of parasitism. The tuatara (Sphenodon punctatus) (Reptilia: Sphenodontia) is a threatened reptile that persists at high densities in forests (approximately 2700 tuatara/ha) and lower densities in pastures and shrubland (< 200 tuatara/ha) on Stephens Island, New Zealand. We investigated the lifecycles and seasonal dynamics of infestation of two ectoparasites (the tuatara tick, Amblyomma sphenodonti, and trombiculid mites, Neotrombicula sp.) in a mark-recapture study in three forest study plots from November 2004 to March 2007, and compared infestation levels among habitat types in March 2006. Tick loads were lowest over summer and peaked from late autumn (May) until early spring (September). Mating and engorgement of female ticks was highest over spring, and larval tick loads subsequently increased in early autumn (March). Nymphal tick loads increased in September, and adult tick loads increased in May. Our findings suggest the tuatara tick has a 2- or 3-year lifecycle. Mite loads were highest over summer and autumn, and peaked in March. Prevalences (proportion of hosts infected) and densities (estimated number of parasites per hectare) of ticks were similar among habitats, but tick loads (parasites per host) were higher in pastures than in forests and shrub. The prevalence and density of mites was higher in forests than in pasture or shrub, but mite loads were similar among habitats. We suggest that a higher density of tuatara in forests may reduce the ectoparasite loads of individuals through a dilution effect. Understanding host-parasite dynamics will help in the conservation management of both the host and its parasites.

Brood‐switching in Eagle Owl Bubo bubo fledglings

Nest-switching, the (permanent or temporary) intrusion of one or several foreign young in another brood (which gener ally occurs when fledglings are capable of flight but are not yet completely independent of parents) and their sub sequent adoption by a foster family (parents + native young), has been recorded in many bird species (Riedman 1982). These include several birds of prey (Ospreys Pandion haliaetus , Poole 1982, Gilson & Marzluff 2000; Eurasian Sparrowhawks Accipiter nisus , Wyllie 1985; American Kestrels Falco sparverius , Lett & Bird 1987; Egyptian Vultures Neophron percnopterus , Donazar & Ceballos 1990; Black Kites Milvus migrans and Red Kites Milvus milvus , Bustamante & Hiraldo 1990; Northern Goshawks Accipiter gentilis , Kenward et al. 1993; Spanish Imperial Eagles Aquila adalberti , Ferrer 1993; Lesser Kestrels Falco naumanni , Tella et al. 1997; Montagu’s Harrier Circus pygargus , Arroyo & Garcia 2002) and owls (e.g. Barn Owl Tyto alba , Roulin 1999). One of the most intriguing aspects of this form of alloparental care (Riedman 1982) is the investment of resources by birds into non-genetic offspring, instead of allocating breeding effort exclusively to their own genetic contribution to future generations. Such behaviour seems incompatible with classic evolutionary theory, because it apparently violates the Darwinian principle by which selection does not act to benefit competing genotypes. To explain adoptions in birds, several hypotheses have been invoked and tested. The potential explanations for nest-switching and alloparental care form two main groups (see reviews in Redondo et al. 1995, Bize et al. 2003). First, there may be adaptive explanations such as (1) benefit to fledglings (e.g. better care than in the natal nest, acquisition of a dominant rank within a younger brood, reduction of the ectoparasite load), and (2) kin-selected benefits from a parental perspective when young switch to nests of related adults, diluting predation risk, or increasing breeding experience of related individuals. Secondly, there may be non-adaptive explanations such as reproductive errors or adoptions with negligible costs which do not affect reproductive success or survival of the foster parent. The different intensities of selection pressure for intruder chicks (surviving vs. dying) and foster parents (cost of investment in unrelated fledglings) can also be conceived of as an arms race (Pierotti & Murphy 1987). Under such a scenario, chicks are likely to ‘win’ (and consequently gain adoption) because the selection pressure is stronger than on foster parents to discriminate and reject intruders. Here, we report detailed observations of two cases of nest-switching in radiotagged Eagle Owl Bubo bubo fledglings and discuss them in an evolutionary context. Because nest-switching occurred during the post-fledging dependence period (i.e. owlets were no longer in the nest because they abandon it completely), hereafter we consider it more appropriate to replace the term nest-switching with brood-switching.

Ectoparasite load is linked to ontogeny and cell-mediated immunity in an avian host system with pronounced hatching asynchrony

Several contrasting hypotheses have been proposed to account for host age-biased parasite distribution, with some of them suggesting a key role of ectoparasites in the evolution and maintenance of weight hierarchies within broods. We examined parasite distribution among individual hosts across the whole period of host exposure to the parasite in a host system that shows distinct within-brood differences in age and age-related mortality. By contrast to previous hypotheses, we found that the abundance of a haematophagous, mobile ectoparasite Carnus haemapterus on nestling European rollers (Coracias garrulus) was highest approximately during the mid-nestling stage of their host, coinciding with the inflection point of the host growth phase. Parasite load increased neither with absolute resource availability (i.e. body size), nor body condition index. By contrast to previous evidence, higher parasite load under natural conditions was associated with a stronger cell-mediated immune response. However, this association was moderated by low parasite densities, as well as a better brood body condition index. Overall, although we revealed remarkable host ontogenetic effects on parasite distribution, the present study suggests that a highly mobile ectoparasite generally prefers healthier hosts. We propose that, in host systems with a marked asynchrony of hatching and background mortality within the brood, parasites favour persistence rather than nutritional attractiveness of the host.

Variation in Ectoparasite Load Reflects Life History Traits in the Lesser Mouse-eared Bat Myotis blythii (Chiroptera: Vespertilionidae) in Western Iran

We studied seasonal variation of ectoparasite load (number of parasites per individual bat) in free-ranging populations of the lesser mouse-eared bat Myotis blythii in western Iran. Data for 1 species each of batfly (Nycteribidae), tick (Ixodidae), and mite (Spinturnicidae) are reported for a 1 yr period. Patterns of parasite load during this time differed considerably among species. However, the parasite load increased markedly in pregnant females in spring and early summer. During the same time frame, parasite load decreased in solitary males when they roosted apart from maternity clusters. However, in late summer, when bats began swarming, males showed a significant (P < 0.05) increase in parasite load. Using the ratio of body mass to length of forearm as an index of body condition, no significant correlation was found.

Does cleanerfish service quality depend on client value or choice options?

Cleaning fish mutualisms appear to be good examples of biological markets. Two classes of traders exist: cleaner fish and their fish clients, each of which supplies a commodity required by the other (ectoparasite removal and a meal, respectively). However, clients are not all treated similarly by cleaners. There is evidence that clients with choice options (with potential access to more than one cleaner) have priority of access over clients without choice options. Market theory predicts that client value (i.e. ectoparasite load) should also influence cleaning service quality. We examined the relative roles of client choice options and client value in determining the duration of cleaning interactions between bluestreak cleaner wrasse, Labroides dimidiatus, and their clients across three geographically distant sites. We found a lack of covariation between client choice options and gnathiid ectoparasite loads. Geographical differences in gnathiid availability altered the importance of client gnathiid load as a determinant of client inspection duration. As predicted, clients with both choice options and high gnathiid loads were inspected for longer, but this was observed only in an area with a relatively high incidence of parasitism. These correlational results suggest that the importance of client choice for aspects of cleaner fish service quality may be modulated by parasite availability.

Costs and benefits of polygyny in the cichlid Neolamprologus pulcher

Polygyny is regarded as a beneficial strategy for males, whereas females mated with polygynous males (males simultaneously paired to more than one female) often suffer a reduction in pair male contributions. This study examined the costs and benefits associated with polygyny in the cooperatively breeding cichlid Neolamprologus pulcher. In this species, males are facultatively polygynous; some males hold only one territory with one breeding female whereas other males hold multiple territories, each with its own breeding female. Polygynous males were larger than monogamous males and body-scraped less, a behaviour often associated with ectoparasite loads. Polygynous males also had larger testes (controlling for body mass) and higher circulating 11-ketotestosterone levels than monogamous males. Paradoxically, monogamous males occupied higher-quality territories with more shelter and fewer predators. Monogamous males also provided more parental care than polygynous males but the number and survival of young did not vary according to male mating behaviour. The results of our study suggest that females trade-off between male genetic quality and resources in N. pulcher. Our results imply that males holding only one territory may provide their mates with significant assets but may not be able to outcompete neighbours for additional breeding positions because of their small body size and possible higher parasite load. The lack of differences between monogamous and polygynous groups in terms of offspring survival (a measure of reproductive success) suggests that there may be few if any fitness consequences of polygynous pairing for females.

The Meaning of Jolts by Fish Clients of Cleaning Gobies

AbstractCooperative interactions offer the inherent possibility of cheating by each of the interacting partners. A key challenge to behavioural observers is to recognize these conflicts, and find means to measure reliably cheating in natural interactions. CleanerfishLabroides dimidiatuscheat by taking scales and mucus from their fish clients and such dishonest cleaning has been previously recognized in the form of whole‐body jolts by clients in response to cleaner mouth contact. In this study, we test whether jolts may be a general client response to cheating by cleaners. We experimentally varied the ectoparasite loads of yellowtail damselfish (Microspathodon chrysurus), a common client of the cleaning gobyElacantinus evelynae, and compared the rates of jolts on parasitized and deparasitized clients. As predicted if jolts represent cleaner cheating, deparasitized clients jolted more often than parasitized clients, and overall jolt rates increased over time as client parasite load was presumably reduced by cleaning activity. Yellowtail damselfish in the wild jolted significantly less frequently than those in captivity, which is consistent with a loss of ectoparasites during capture. Our results suggest that jolts by clients of cleaning gobies are not related to the removal of ectoparasites. Client jolts may therefore be a generally accurate measure of cheating by cleanerfish.

The influence of sex and sociality on parasite loads in an African ground squirrel

Male-biased parasite loads, which are common in vertebrates, could be a consequence of sexual selection, and for species that group, the costs of parasites could vary with group size or social structure. We examined sex-biased parasitism and the influence of group size on parasite loads in Cape ground squirrels (Xerus inauris), a highly social species that occurs in the arid regions of southern Africa. Group size did not affect numbers of ectoparasites or endoparasites. Males carried 3 times as many ectoparasites as females, but females harbored nearly 3 times as many endoparasites as males. Age class did not affect parasite loads in females, but in males, adults carried more ectoparasites than juveniles. Allogrooming was performed primarily by females, but no sex difference was found in autogrooming. Males in the subadult age class are becoming scrotal (indicating an increase in sex hormones) but typically remain in the natal group until adulthood, maintaining home range sizes comparable to adult females. Our results suggest that sexual selection does influence parasite loads in this species; increased androgen levels may reduce ectoparasite resistance in males, and smaller home ranges may increase females’ exposure to endoparasites. Allogrooming could reduce ectoparasite loads of the group and mitigate the costs of grouping. Key words: ectoparasite, endoparasite, fleas, group size, grooming, lice, sex-biased parasitism, sexual selection, ticks. [Behav Ecol]

A comparative study of cleaning activity of two reef fishes at Fernando de Noronha Archipelago, tropical West Atlantic

Cleaner fishes are usually classified as obligate or facultative cleaners according to their diet and the extent to which their nutritional requirements in the different ontogenetic stages are gained from cleaning. While obligate cleaners clean throughout their lives and ingest mainly food taken from the clients’ body surface, facultative cleaners clean only as juveniles and have a broader diet. In addition, some facultative cleaners may experience a relatively higher predation risk, and thus rarely interact with piscivorous fishes. Despite these acknowledged differences, there are very few studies that compare cleaning activity of obligate and facultative cleaners within the same area. Cleaning activity of the obligate cleaner goby Elacatinus cf. randalli and the facultative cleaner wrasse Thalassoma noronhanum were comparatively examined at Fernando de Noronha Archipelago, tropical West Atlantic. The client assemblage attended by the two cleaners differed, as the goby attended a slightly greater diversity of species (22), mostly piscivores and zoobenthivores, and the wrasse attended fewer species (19), mostly planktivores. Chromis multilineata was the most common client species of both cleaners, although body size (which is expected to be positively correlated to clients’ ectoparasite load) of C. multilineata individuals attended by the goby was larger than that of the individuals attended by the wrasse. Despite such differences, T. noronhanum showed a surprisingly species-rich client assemblage when compared with other cleaners of the genus Thalassoma. In addition, the frequency and time spent on cleaning interactions, as well as the number of client species attended per 10-min period, was similar for both cleaner species, which indicate that they have important yet complimentary ecological roles in the reef community at Fernando de Noronha Archipelago.

Nestling begging intensity and parental effort in relation to prelaying carotenoid availability

Carotenoids are antioxidants playing major roles in physiological functions at various stages of an animal’s life. Female birds deposit large amounts of carotenoids into their eggs. Carotenoids are, however, a limiting resource, and females are expected to balance carotenoid deposition into the eggs with their utilization for themselves. Carotenoid availability is thus likely to determine both the levels of yolk carotenoids and maternal care during rearing. Carotenoids have been shown to benefit the embryo and the growing nestling, and it can be hypothesized that an increase in carotenoid availability during laying leads to higher nestling condition and competitive ability. We manipulated carotenoid availability to great tit pairs prior to and during egg laying and later partially cross-fostered chicks at hatching. During the rearing period, we measured how carotenoid availability affected nestlings begging behavior and male and female feeding effort. We also manipulated the ectoparasite load, predicting that carotenoid supplementation would help adults and nestling to cope with parasites. Nestlings hatched from eggs laid by carotenoid-supplemented females and raised in small broods begged more intensely. Nestlings in small deparasitized broods also begged more actively. The feeding effort of control females increased with brood size, whereas the feeding effort of carotenoidsupplemented females was high whatever the brood size. Male feeding effort was unaffected by our treatment. Our results support the hypothesis that maternally derived carotenoids increase nestling begging behavior and hence competitive ability. They further suggest that carotenoid availability determines the level of parental investment and can mediate trade-offs between life-history traits. Key words: begging, food provisioning, maternally derived carotenoids, parasites, parental care, reproductive investment. [Behav Ecol]

Common paths link food abundance and ectoparasite loads to physiological performance and recruitment in nestling blue tits

Summary 1Identifying how selection shapes life-history traits by causally relating environment to phenotype, performance and fitness has often proven elusive due to limitations of classical analysis methods, which only identify covariance in traits, and to the difficulties in experimentally manipulating environment to expose cause and effect in wild populations. 2In an approach resembling the experimental method common to all modern research, structural equation modelling can not only identify covariance in traits, but also test hypotheses of direct and indirect causal paths that tie environment to phenotypes and fitness through natural selection. Here, we use novel confirmatory path analyses and a long-term study of Corsican blue tits to analyse the interactions between environmental variables (prey abundance and ectoparasite load), phenotypic traits (mass and haematocrit), physiological performance (aerobic capacity) and nestling recruitment. 3Our analyses show that an antagonistic interaction between ectoparasites and food abundance sets tissue development and oxygen carrying capacity of blood at fledging, and that identical paths link these variables to physiological performance and recruitment. 4This study suggests that metabolic capacity at fledging may be important in determining subsequent recruitment and unmasks subtle fitness costs of an ectoparasite.

Cavity Nest Materials of Northern Flying Squirrels, &lt;em&gt;Glaucomys sabrinus&lt;/em&gt;, and North American Red Squirrels, &lt;em&gt;Tamiasciurus hudsonicus&lt;/em&gt;, in a Secondary Hardwood Forest of Southern Ontario

Through deployment of artificial nest boxes, we examined the composition of cavity nest materials used by Northern Flying Squirrels (Glaucomys sabrinus) and North American Red Squirrels (Tamiasciurus hudsonicus) in a secondary hardwood forest of southern Ontario, Canada. We collected 32 nests of known species association and found that 85.7% of G. sabrinus nests and 77.8% of T. hudsonicus nests were constructed almost entirely of shredded bark from Eastern White Cedar (Thuja occidentalis). Mean nest depth across all samples was 12.2 cm and showed no significant difference between species or between spring and summer nests. We review the antiparasitic properties of T. occidentalis and suggest that the use of shredded cedar bark by G. sabrinus and T. hudsonicus to line nest cavities may be a behavioural adaptation, which reduces ectoparasite loads in the nest environment.

FACTORS INFLUENCING MOVEMENT PROBABILITIES OF BIG BROWN BATS (EPTESICUS FUSCUS) IN BUILDINGS

We investigated movements of female big brown bats (Eptesicus fuscus) roosting in maternity colonies in buildings in Fort Collins, Colorado (USA), during the summers of 2002, 2003, and 2005. This behavior can be of public health concern where bats that may carry diseases (e.g., rabies) move among buildings occupied by people. We used passive integrated transponders (PIT tags) to mark individual bats and hoop PIT readers at emergence points to passively monitor the use of building roosts by marked adult females on a daily basis during the lactation phase of reproduction. Multi-strata models were used to examine movements among roosts in relation to ambient temperatures and ectoparasite loads. Our results suggest that high ambient temperatures influence movements. Numbers of mites (Steatonyssus occidentalis) did not appear to influence movements of female bats among building roosts. In an urban landscape, periods with unusually hot conditions are accompanied by shifting of bats to different buildings or segments of buildings, and this behavior may increase the potential for contact with people in settings where, in comparison to their more regularly used buildings, the bats may be more likely to be of public concern as nuisances or health risks.

Experimental addition of greenery reduces flea loads in nests of a non‐greenery using species, the tree swallowTachycineta bicolor

Several bird species, including cavity‐nesters such as European starlingsSturnus vulgaris, add to their nests green sprigs of plants such as yarrowAchillea millefoliumthat are rich in volatile compounds. In this field study on another cavity‐nester, tree swallowsTachycineta bicolor, we tested whether yarrow reduced ectoparasite loads (the nest protection hypothesis), stimulated nestling immune systems (the drug hypothesis), or had other consequences for nestling growth or parental reproductive success (predicted by both preceding hypotheses). Tree swallows do not naturally add greenery to their nests, and thus offer several advantages in testing for effects of greenery independent of other potentially confounding explanations for the behaviour. We placed fresh yarrow in 23 swallow nests on the day the first egg was laid, replenishing every two days until clutch completion (=three times), and at 44 control nests, nesting material was simply touched. At 12 days of age, we measured nestling body size and mass, and took blood smears to do differential white blood cell counts. We subsequently determined the number and proportion of young fledging from nests and the number of fleas remaining after fledging. Higher humidity was associated with higher flea numbers whereas number of feathers in the nest was not. Our most significant finding was that an average of 773 fleasCeratophyllus idiuswas found in control nests, versus 419 in yarrow nests. Possibly, parents compensate for blood that nestlings lose to ectoparasites by increasing food delivery, because we detected no differences between treatments in nestling mass, nestling leukocyte profiles, or proportion of young fledging, or relative to flea numbers. Our results provide no support for the drug hypothesis and strong support for the nest protection hypothesis.

ECTOPARASITES IN AN URBAN POPULATION OF BIG BROWN BATS (EPTESICUS FUSCUS) IN COLORADO

Ectoparasites of an urban population of big brown bats (Eptesicus fuscus) in Fort Collins, Colorado, were investigated during summers 2002, 2003, and 2004. Eleven species of ectoparasites were found (the macronyssid mite Steatonyssus occidentalis, the wing mite Spinturnix bakeri, the myobiid mites Acanthophthirius caudata and Pteracarus aculeus, the chirodiscid mite Alabidocarpus eptesicus, the demodicid mite Demodex sp., the chigger Leptotrombidium myotis, the soft tick Carios kelleyi, the batfly Basilia forcipata, the batbug Cimex pilosellus, and the flea Myodopsylla borealis). Five species were analyzed by prevalence and intensity (C. pilosellus, M. borealis, L. myotis, S. bakeri, and S. occidentalis) based on 2161 counts of 1702 marked individual bats over the 3 summer study periods. We investigated 4 factors potentially influencing prevalence and intensity: age class of the host, reproductive status of adult female hosts, roosts in which the hosts were found, and abiotic conditions during the year sampled. The macronyssid mite, S. occidentalis, was the most prevalent and abundant ectoparasite. Adult big brown bats had more ectoparasites than volant juveniles for most of the species analyzed. In a sample of known age bats at 1 large colony, bats of 4 yr of age or greater had higher ectoparasite loads of S. occidentalis and S. bakeri when compared with younger bats. Lactating female bats had the highest prevalence and intensities of most ectoparasites. Annual differences in ectoparasite prevalence and intensity were related to temperature and humidity, which can affect the nidicolous species of ectoparasites. Residents of 2 buildings sprayed insecticides in response to Cimex sp., and this appeared to reduce ectoparasitism of S. occidentalis and C. pilosellus present at these buildings. Intensity of S. occidentalis had no influence on annual survival of big brown bats.

Experimental and molecular evidence that body size and ventral colour interact to influence male reproductive success in a lizard

This study aimed to first investigate the relationship between male ventral colour, body size and ectoparasite load, and then test, using an enclosure experiment, how body size and ventral colour influence male reproductive success in a non-territorial lizard. Individuals of the sexually dimorphic Australian skink, Pseudemoia entrecasteauxii, were sampled in the field and male body size and ventral coloration were recorded. The frequency of orange and white ventral colour appeared bimodal; males either had orange or white ventral colour. While larger males were more likely to have orange ventral colour, there was considerable variation and small males with orange ventral colour and large males with white ventral colour were common. The number of mites each male had was positively correlated with snout vent length, weight and head depth corrected for body size and was greater for males with orange ventral colour. Mating trials in outdoor enclosures were used to investigate the separate and combined effects of male ventral colour, body size and male behavior on reproductive success. Behavioural observations revealed that males with orange ventral colour were dominant over males with white ventral colour and, contrary to expectations, male body size was not related to dominance. A total of 32 neonates were genotyped along with their mothers and potential fathers using three polymorphic DNA loci. Large males with orange ventral colour fathered the most neonates. These findings suggest that although males with orange ventral colour were dominant, both body size and ventral colour influenced male reproductive success.