The kodkod Oncifelis guigna has one of the smallest distributions of wild felids, being geographically restricted to a narrow strip within Chile and Argentina. An investigation of population demography and habitat selection was carried out using trapping and radio-telemetry techniques in transitional Valdivian forest at two sites in southern Chile. The mean home-range size was estimated at 269 ha with considerable overlap of ranges and core areas giving a density of combined adults and sub-adults of 0.97/km2. Forest, thicket-forest, and scrub-thicket predominated in the ranges of most individuals and habitats at less than 50 m elevation were more frequently used than higher slopes. With the exception of páramo and thicket, all other habitat types were used more frequently than expected by at least one of the kodkods. The study confirmed the strong habitat association with Valdivian and Araucaria forests previously reported for this species, but also suggested a more flexible use of habitat within home ranges and individual preferences of habitat used as core areas. Flexibility in resource use and mutual avoidance may explain why kodkod ranges overlap and populations reach high densities locally. This high degree of adaptability may well be relevant to the long-term survival of this species in an ever increasing, anthropogenically-modified environment.

The general aim of the present study was to test whether there are differences in the occlusal design of the ruminant selenodont molar, and by examining correlations between tooth form and diet, improve our understanding of the function of the selenodont molar within the Bovidae. Twenty-six species of bovid ruminants were grouped into the three feeding types established by Hofmann (1968) – i.e. browsers, grazers and intermediate feeders. The characteristics of the shape, number, width and length of the enamel ridges were found to correlate with the hypothesized function of the molar occlusal surface. These follow the principles applied to non-bovid species where adaptation of the occlusal surface has been investigated in some detail. Thirteen characteristics of the occlusal surface were scored. ANOSIM results reject the null hypothesis that there are no differences in the selenodont molar occlusal surface. SIMPER results showed that all the characteristics scored contributed to the differences between groups, and crown height was not explaining the major dissimilarity between feeding groups. Differences in enamel ridge characteristics between feeding types suggest that food is being processed in essentially different ways by the browsers and grazers. Intermediate feeding species cluster within the other feeding types, depending on what the major component of the diet is. The grouping produced by the MDS, based on dental characters, closely agrees with Hofmann's classification based on gut structure.

The echolocation calls of insectivorous bats of the northern Yucatan Peninsula, Mexico, with the exception of the phyllostomids and molossids, are presented. The aim is to provide a catalogue of bat sounds that can be used for acoustic inventories of insectivorous bats using the Pettersson heterodyne and time-expansion bat detectors. The acoustic method can be used alone or in combination with inventories based on mist-netting, a method more suitable for the low-intensity echolocators (mainly the phyllostomids), which are difficult to monitor acoustically. The insectivorous species of the Yucatan are generally easy to identify by their echolocation calls, particularly when combined with visual observations of foraging bats at dusk.

The relationships between radio-collaring/tracking and 12 biometric parameters in a population of badgers (Meles meles) that were live-trapped in south-west England were investigated. The length of time for which a badger had worn a radio-collar was selected as an explanatory variable in generalized linear models of three biometric parameters (body condition, body weight and testes volume) irrespective of whether or not age class was included as a variable in the analyses. There was evidence that badgers that had been carrying a radio-collar for 1–100 days had lower body condition scores both when compared to badgers that had not been collared and with those that had been collared for longer than 100 days, suggesting a post-collaring acclimation period. In addition, the time period between first and last capture was longer for radio-collared than non-collared badgers. It is unlikely that this was due to an effect of collaring on trappability or to non-random selection of badgers for collaring. Although testes size differed between non-collared badgers and badgers that had been tagged for > 100 days, the relationship between radio-collaring and reproductive output remained unproven. These results highlight not only the need to assess the welfare aspects of radio-collaring but also the potential intricacy of corollaries of collaring. Explorations such as that reported here are important to the validity of studies that make use of radio-telemetry.

Sperm-dependent parthenogens are expected to promote higher female fecundity at the expense of the production of excessive numbers of sperm. They are also expected to trade sperm strictly, in order to compensate for the loss of nutrients invested in sperm, that otherwise could be allocated to the female function. In this paper, we present evidence that in a natural population of the freshwater planarian Girardia (= Dugesia) tigrina, sperm-dependent parthenogenesis is alternated with fissipary, a combination not reported before for freshwater flatworms. More specifically, we found that most individuals that engage in a copulation have no or only few testes and sperm available, despite the presence of a fully developed penis, indicating that male allocation is fairly low in this (dense) population. Female fecundity on the contrary is rather high, with isolated individuals producing up to six fertilized cocoons over a 3-week period, releasing five young per cocoon on average. An analysis of the mating behaviour further shows that matings in this species are simple and direct with no distinct courtship behaviour. Copulations last for about 36 min and occur at a rate of at least one copulation a day. Bilateral sperm transfer is the rule, but a considerable number of copulations are unidirectional or without sperm transfer. Non-reciprocal inseminations mainly result from the fact that one or both partners has no sperm stored prior to copulation, indicating that strict sperm trading plays no role in this population of G. tigrina.

Because sensory capacities and responsiveness must correspond to adaptively important environmental cues, they may require evolutionary modification to match shifts in the adaptive milieu. Many lizards identify prey by tongue-flicking, especially actively foraging species of Scleroglossa, the speciose lizard taxon that includes snakes. Correspondence between diet and chemosensory responsiveness, although known in two genera of colubrid snakes, has not been established in lizards because most species are generalist predators. Omnivory and herbivory are uncommon among scleroglossans, but have evolved frequently enough to permit tests of the hypothesis that shifts to plant consumption have been accompanied by acquisition of responsiveness to plant food chemicals. Based on literature surveys I traced the evolution of scleroglossan lizard diet and food chemical discrimination. Three tests taking phylogenetic relationships into account (concentrated changes tests, Pagel's tests, and a modification of Ridley's test) showed that correlated evolution has occurred, with strong responses to plant chemicals having evolved convergently in at least five taxa that underwent shifts from insectivory to omnivory or herbivory. In all four origins of omnivory and herbivory in taxa derived from ancestral active foragers, lizards retained prey chemical discrimination. In the single origin of omnivory in an ancestrally ambush foraging taxon, both plant and prey chemical discrimination evolved de novo. These findings show that one aspect of chemosensory identification of food has been evolutionarily adjusted to diet in a major group of vertebrates.

Diploid and tetraploid populations of the leptodactylid frog Odontophrynus americanus were studied in the Cordoba province (central Argentine) to evaluate whether they represent a cryptic species pair rather than forms of the same species as they are considered at present. We examined three independent character complexes (external morphology, advertisement calls, allozymes) and quantified the character-specific state of differentiation between diploids and tetraploids in comparison to that of the congeneric and widely sympatric O. occidentalis. Multivariate analysis of 15 morphometric characters indicated a remarkable degree of differention between both forms, but did not permit an unequivocal identification of individuals (rate of erroneous classification: 25%), whereas all O. occidentalis were classified correctly. In contrast, the temporal structure of the advertisement call permitted a distinction of diploids, tetraploids and O. occidentalis even based on a single call. The latter differed from the other by producing a call consisting of several pulse trains. The pulse rate of the O. americanus call, which consists of a single pulse train, was significantly lower in tetraploids than in diploids. The allozyme pattern and the corresponding allele frequencies indicated a close relationship among the three Odontophrynus taxa, but genetic distances obtained suggested a differentiation of gene pools at the level of species. Considering the degree of differentiation demonstrated in this study, the ploidy and the different geographical distribution, we conclude that diploids and tetraploids represent two species, similar to its North American counterpart Hyla chrysoscelis/H. versicolor. As the name O. americanus refers to tetraploids collected near Buenos Aires (Argentina), we describe the diploids as the new species Odontophrynus cordobae sp. nov.

The development of the male duct and spermatheca is studied in three species of the marine Limnodriloidinae (Tubificidae): Limnodriloides rubicundus; Tectidrilus bori; Thalassodrilides ineri. All tubificids are hermaphroditic with paired male ducts, female ducts and, as a rule, spermathecae. The male duct comprises a funnel, followed by a vas deferens, an atrium and, frequently, a copulatory structure. There may also be a diffuse or compact prostate gland in association with the male duct. In the three species studied, the funnel and vas deferens originate from peritoneal (mesodermal) cells in the posterior septa of the testes segment. The atrium develops from an invagination of the epidermis (ectoderm). The vas deferens and atrium subsequently connect to each other, and a continuous duct from the testes segment to the exterior is formed. The prostate gland originates from large peritoneal cells occurring in a delimited area on the outer surface of the atrium; other small peritoneal cells surrounding the whole atrium give rise to muscle fibres. The spermatheca develops from an invagination of the epidermis, and is thus of ectodermal origin. The morphology and position of the genital ducts have been and are important for the classification of the oligochaetes. However, different parts of the male duct have been named without regard to whether they are homologous or not. One way to establish stronger primary hypotheses of homology is to study the detailed morphology and/or the development of the genital ducts.

Can variation in egg size explain the local variation in tadpole growth and development of the common frog Rana temporaria or are other mechanisms, e.g. microevolution, involved? To study this, tadpoles were raised in outdoor tanks. Each tank housed tadpoles from one clutch. Eggs were collected during 2 years from six different ponds and their sizes were measured. Large eggs gave rise to tadpoles that grew and developed faster than those hatched from small eggs. Tadpoles from large eggs thus metamorphosed earlier but, because they grew for a shorter time, size at metamorphosis was not affected by initial egg size. Tadpoles from different ponds differed in strategy; after correcting for egg size effects, tadpoles from some ponds tended to metamorphose earlier and at a larger size than those from others. These ponds occasionally dry out during or before the tadpoles' period of metamorphosis. I argue that the detected pond differences are genetically based and represent a case of microevolution.

The diet of the blackwidow spider Latrodectus lilianae (Araneae: Theridiidae) was studied in an arid shrub-steppe of south-eastern Spain during 1990–93. For the first 3 years, prey mummies attached to spider webs were collected once the spiders' activity period was finished, at the end of September. In the fourth year, webs were marked and checked bi-weekly from April to September during the activity period of the blackwidow spider. We identified 2106 prey items from 164 webs. Most prey were Tenebrionidae and Oniscidae, which together represented from 65.4% to 82.0% in frequency and from 78.6% to 92.0% in biomass of all prey. An analysis of selectivity comparing prey availability from prey collected in pitfalls and those collected in the webs showed that spiders preferred Tenebrionidae and Oniscidae. However, an analysis of prey size reflects also that spiders mostly selected prey ranging from 12.5 to 22.5 mm long, suggesting that prey size, rather than taxon, determines prey capture. Other predatory arthropods, as well as five small lizards, were found as prey of the blackwidow spider. This suggests that the blackwidow spider may play an essential role in regulating the food web and trophic structure in this community by preying on other species that potentially compete with or prey upon blackwidow spiders.

Management of whale shark Rhincodon typus populations is hampered by a lack of information on the range travelled by individual whale sharks. This applies particularly in South-east Asia where the whale shark is increasingly used in commercial trade and for ecotourism. In this study an investigation of the movements of individual whale sharks from the greater Sulu Sea region was initiated using satellite telemetry. The movements of six sharks were monitored from 7 to 128 days. Two sharks travelled distances of 4567 and 8025 km. Both sharks moved through multiple political jurisdictions, confirming the need to manage the populations on a multilateral or regional level.

Armadillos are a very diverse group ranging from non-fossorial Tolypeutini through to the powerful diggers like the giant armadillo Priodontes maximus to the totally subterranean Chlamyphorini. A previous study demonstrated a close relationship between the relative length of the olecranon of the ulna (index of fossorial ability, IFA) and the fossorial ability of armadillos. This study examines a wide range of limb proportions to explore the biomechanical correlates with fossorial ability. The study demonstrates that the indices of the forelimb (brachial index, shoulder moment index and IFA) do correlate well with digging habits, but also reveals some interesting exceptions, particularly in the most fossorial and most cursorial forms. On the other hand, the hindlimb indices apparently do not correlate with digging habits, but seem to be influenced more by body size. The correlations among the forelimb indices are quite strong and positive but correlations between forelimb and hindlimb indices are negative or very low. It is apparent that there is still much to be learned about structure and function in armadillos.

In our study area in Zimbabwe, half of the fresh-weight biomass of the diet of side-striped jackals Canis adustus comprised small and medium-sized mammals, and a further third consisted of fruit. Three types of mammal (multimammate mice Mastomys spp., bushveldt gerbil Tatera leucogaster and scrub hare Lepus saxatilus) and four species of fruit (mobola plum Parinari curatellifolia, chocolate berry Vitex payos, wild fig Ficus natalensis and waterberry Syzigium guineense) dominated these categories. Captive jackals significantly preferred animal prey items to fruits, and these were also the items that contained the highest levels of apparent available energy and organic matter. Wild jackals, however, did not spend more time in the habitats in which mammals were most abundant, nor did they eat more of them during a period of higher prey population density. We conclude that the feeding of jackals is largely geared by searches for fruit, and that mammals are taken opportunistically when they are encountered.