A study of individually marked smooth snakes Coronella austriaca was carried out in Wareham Forest, southern England between 1992 and 2001. On average, approximately one-third of potential breeding females reproduced each year and within this group, the proportion breeding was positively correlated with snout–vent length (SVL). Successful breeders had a higher than average body condition at the start of the breeding year compared with unsuccessful breeders. The density of gravid females was positively correlated with prey density in the breeding year but not in the year preceding it. No significant relationships were found between the density of non-breeding females and prey density in either the breeding year or the preceding year. Although most breeding females did not produce young in consecutive years, a small proportion did. There was a weak positive relationship between clutch size and female SVL. This study suggests that the potential for female smooth snakes to breed is provided by stored energy reserves but that this potential is regulated by prey availability in the breeding year.

The main objective of this project was to provide baseline data on faecal parasites of groups of non-human primates from Tambopata Research Center, Tambopata National Reserve, Peru. All primate species found in this area were sampled: red howler monkeys Alouatta seniculus, night monkeys Aotus vociferans, spider monkeys Ateles bezlebuth chamek, brown titi monkeys Callicebus brunneus, white-fronted capuchins Cebus albifrons, brown capuchins Cebus apella, saddleback tamarins Saguinus fuscicollis and squirrel monkeys Saimiri sciureus. Individuals from four howler monkey troops, three brown titi monkey troops, two squirrel monkey troops and one troop each of night monkeys, spider monkeys, brown capuchins, white-fronted capuchins and saddleback tamarins were sampled. Faecal samples were collected from July to October 2002 from 86 individuals. A concentration test was used to analyse faecal samples. Results indicate the presence of various protozoans, Ancyclostoma sp., Ascaris sp., Strongyloides stercoralis, Trichuris trichiura, Prosthenorchis elegans and Schistosoma mansoni.

Heterochrony is commonly proposed as a mechanism producing evolutionary changes, and some researchers identify two ways that heterochrony may be conceptualized. ‘Growth heterochrony’ examines ancestor-to-descendant differences in the ontogeny of size relative to shape, while ‘sequence heterochrony’ focuses on differences in the order of occurrence of events during ontogeny. Methods introduced here are allied with sequence heterochrony in that ontogeny is modelled as if it were a sequence of events; however, events are differently defined in this study. Using data from 16 primate species, I demonstrate that discriminant function analysis of data on developmental timing provides an additional tool for exploring the relationship between ontogeny and phylogeny. Patterns in the timing of tooth eruption, craniofacial sutural closure, and postcranial epiphyseal fusion can be used to classify individuals of all ages to their correct taxon. Taxon differences in these patterns can be characterized and described by interpreting correlations between discriminant functions and developmental events. Discriminant analysis has the advantages of: (1) being applicable to taxa for which there are too few individuals to be able to reconstruct ontogenetic sequences, including fossil species; (2) preserving intraspecific developmental variation during analysis; (3) being sensitive to very subtle differences in ontogenetic timing.

Dikerogammarus villosus, a freshwater invasive amphipod, exhibits conspicuous pigmentation polymorphism. This polymorphism is documented in two recently colonized areas, the Saône and Moselle rivers (north-eastern France), and some of the mechanisms by which pigmentation polymorphism can arise and be maintained are addressed. Body size, reproductive status, fecundity and mate choice are compared among morphs of D. villosus in field samples collected in summer 2001. Body size and female gonad developmental stage were comparable among the different morphs, suggesting that polymorphism is not the result of changes in pigmentation with age or moult-cycle. Fecundity and reproductive status (paired vs non-paired) were not affected by pigmentation morph either. A random combination of morphs in pre-copula pairs was observed, showing that the colour pattern does not play a major role in mate choice. A strong size-assortative pairing was found, and this pattern was similar among male morphs. Overall, our study shows that morph polymorphism is not related to different stages in the moult cycle or the life cycle, and is not maintained by morph-assortative pairing. Alternative explanations to the mate choice hypothesis for the maintenance of pigmentation polymorphism are discussed.

The morphology of insect eyes often seems to be shaped by evolution to match their behaviour and lifestyle. Here the relationship between the nuptial flight behaviour of 10 Atta species (Hymenoptera: Formicidae) and the eye size of male and female alates, including the compound eyes, ommatidia facets, and ocelli were examined. These species can be divided into two distinct groups by nuptial flight behaviour: those that initiate the nuptial flight during the day and those that initiate it at night. The most striking difference between day- vs night-flying alates was in ocellus area, which was almost 50% larger in night-flying species. Night-flying species also had significantly larger ommatidia facets than day-flying species. A scaling relationship was also found between compound eye area, facet diameter, and ocellus area vs overall body size. Detailed observations are also presented on the nuptial flight behaviour of a night- vs day-flying species, A. texana and A. sexdens, respectively. The pattern in A. texana is for a single large and precisely timed nuptial flight before dawn, while flights of A. sexdens last for several hours, beginning at midday. Further observations suggest that the timing of the nuptial flight in A. texana is easily disrupted by light pollution.

The reproductive system is described from 15 giant squid Architeuthis sp., collected between 1972 and 2002 in South African waters. Distinctive features of the male reproductive system are the long muscular terminal organ, with elaboration of the anterior end, and modification of the tips of the ventral arms, probably hectocotilization. The spermatophoric organ has a long finishing gland that extends from the base of the gill. The terminal organ is differentiated internally into three distinct parts, involved in the guidance, storage, protection, expulsion and possibly the coating of spermatophores. Length of spermatophores in the terminal organ varied considerably. Several stages of spermatophores were found, from tentative to false to fully formed spermatophores, within a single animal. Distinctive features of the female reproductive system are a mesentery surrounding the main blood vessels of the ovary and attaching the ovary to the dorsal gladius chamber, multiple branching (at least three times) of the genital aorta that supplies the developing oocytes, high potential fecundity (3.5–6.2×106 oocytes), small eggs and short oviducts that suggest intermittent (extended) spawning. Large concentrations and single spermatangia were found in various places in females, indicating non-specific deposition. The transfer of spermatophores is probably rapid, perhaps because of considerable sexual size dimorphism (at maturity, males are much smaller than females). Implants in males are probably self-induced since the majority were found within reach of the terminal organ opening (primarily on the ventral arms in males).

Insights into the reproductive strategies of crabeater seals Lobodon carcinophagus were obtained from satellite-linked dive recorders deployed during the breeding season. All of the three females and seven males on which instruments were deployed hauled out continuously for extended periods of up to 24 days. The duration of extended haulout is consistent with a lactation period of around 3 weeks. In two cases where dive recorders were deployed on a male and female in the same group, the two animals stayed together on the ice continuously and entered the water at exactly the same time when extended haulout ceased. In both cases the male and female became geographically separated within a short time after entering the water, indicating that the association did not last beyond the period on the ice. Some males had multiple periods of extended haulout, suggesting they may try to find more than one female with which to mate. An optimal reproductive strategy with regard to the time spent on the ice may balance the conflicting needs of a short time imposed by the availability of breeding habitat and a long time to increase the reproductive success of males and females by finding more, or choosing between, mates.

The respiratory turbinates of mammals are complex bony plates within the nasal chamber that are covered with moist epithelium and provide an extensive surface area for the exchange of heat and water. Given their functional importance, maxilloturbinate size and structure are expected to vary predictably among species adapted to different environments. Here the first quantitative analysis is provided of maxilloturbinate structure based on high-resolution computed tomography (CT) scans of the skulls of eight canid and seven felid species. The key parameters examined were the density of the maxilloturbinate bones within the nasal chamber and how that density varied along the air pathway. In both canids and felids, total maxilloturbinate chamber volume and bone volume increased with body size, with canids having c. 1.5–2.0 times the volume of maxilloturbinate than felids of similar size. In all species, the volume of the maxilloturbinates varies from rostral to caudal, with the peak volume occurring approximately midway, close to where airway cross-sectional area is greatest. Interspecific differences among canids or felids in maxilloturbinate density were not consistent with adaptive explanations, i.e. the densest maxilloturbinates were not associated with species living in arid or cold habitats. Some of the observed variation in maxilloturbinate form might reflect a need for both low- and high-resistance pathways for airflow under alternative conditions.

All else being equal, ectotherms should maintain body temperatures (Tbs) favourable for temperature-sensitive biological functions, such as digestion and locomotion. Physical environments in the temperate zone are often thermally variable, however, thus making it difficult to maintain optimum Tbs. Radiotelemetry and a semi-natural enclosure were used to monitor Tbs of grass snakes Natrix natrix at Canterbury, Kent, U.K. Operative temperatures (Tes) were measured using snake models (copper-pipe models) placed in a variety of microhabitats to determine availability of thermoregulatory opportunities. A modification of Huey & Slatkin's (1976) regression model, piecewise regression, was used to evaluate thermoregulatory behaviour. Grass snakes could achieve high mean Tbs (>30°C) most often during midday (08:00–20:00), but only for 55–61% of the study period. Overall, non-gravid snakes maintained higher and less variable mean daytime Tbs than gravid snakes. From piecewise regression, it was determined that grass snakes initiated thermoregulation at a Te of 38.44°C, corresponding to a Tb of 27.7°C. Three main conclusions can be drawn from this study: (1) thermoregulatory opportunities for grass snakes were limited; (2) nonetheless, when conditions were sufficiently warm, there was clear evidence that grass snakes could thermoregulate; (3) contrary to expectation, gravid females actually maintained lower and more variable Tbs than non-gravid females. The consequences of these thermoregulatory patterns for the fitness of snakes have yet to be determined.

Peripatopsis stelliporata sp. nov. from South Africa is described. SEM observations are used to illustrate the similarities and differences between this species and Peripatopsis capensis Grube 1866. The most conspicuous differences in morphology between the two species relate to the structure of the last reduced pair of legs, and the male genital pore, which in P. stelliporata is stellate in shape. Maintaining P. stelliporata in culture allowed timings of births to be recorded and the onset of sexual maturity to be determined. Spermatophores were first noted when the males were c. 4 months old. Females were observed to give birth at 15 months of age. In any female the embryos are all at around the same stage of development, and females gave birth between February and May. Young were born singly or in pairs at intervals of several days. The appearance of the embryos of P. stelliporata and also those of P. capensis collected in 1996 and 1997 was unexpected, as they are transparent apart from the red pigmented gut running from the mouth to the anus. Previously observed embryos of P. capensis were opaque and unpigmented. In appearance these embryos have similarities to those of Opisthopatus cinctipes Purcell 1895, which exhibits a different pattern of embryonic development. Whether or not this difference in appearance of the embryos reflects a transition in the pattern of development is discussed. A modified key for South African Peripatopsidae incorporating P. stelliporata is presented.

The relationships among harem size, adult sex ratio (proportion of males >5 years in the adult population, i.e. males >5 years plus females >2 years) and male age-structure of red deer Cervus elaphus were investigated in La Petite Pierre National Reserve (PPNR) in France. We tested whether: (1) increasing adult sex ratio leads to a decrease in harem size along with an increase in the number of harems within a given rut period; (2) whether participation of sub-adult males in mating activities increases with decreasing adult sex ratio, and as the proportion of adult males decreases. Harem size did not vary over the mating period, suggesting a high turnover of harem-holders leading to an increase in the costs of mating for males. Harem size averaged 1.43±0.91 and was lower than harem sizes typically reported for red deer (e.g. >2.5 in Scotland and Norway). In support of the first prediction, a decrease in harem size and an increase in the total number of harems seen with an increasing sex ratio was observed (harem size=2.08−1.26 [±0.43]×(sex ratio); r2=0.25, F1,18=6.19, P=0.02). Both the uniform distribution of females among harem stags and the small harem sizes observed in PPNR might concur to a smaller variance in male reproductive success than previously reported in red deer. Lastly, in partial support of the second prediction, the proportion of sub-adult males observed during the mating season decreased with increasing adult sex ratio and with increasing proportions of adult males. Whether or not the lower proportion of sub-adults seen when competition among mature males increases means that fewer young males mate cannot be assessed from our study.

Separation of low digestible fibres and fermentation of the digestible part of the food in the caecum is an adaptation of some small herbivores to cope with low-quality forage. The caecum content is later re-ingested as soft faeces so that the herbivore can benefit from this protein-rich material. This is known as caecotrophy and is a common phenomenon in species of leporids, although differences exist between hares and rabbits. Hares have amorphous soft faeces and the amount of soft faeces produced is smaller compared to that of rabbits. Both factors suggest that hares have smaller benefits from re-ingestion of the caecal contents compared with rabbits and, as a consequence, have a less efficient digestion (mainly of nitrogen) compared to rabbits. The assertion was tested whether digestive efficiency is different between the two herbivores and how this affects the choice of food plants in a natural situation. A feeding trial was conducted using hares and rabbits fed with diets with a range of fibre contents. Dry matter digestibility was not different, but nitrogen digestibility was lower in hares than in rabbits, indicating a less efficient digestion of protein. Both taxa showed a different response to increased fibre content in the diet. Rabbits maximized digestibility by increasing retention time of the food, hares maximized digestion rate by increasing the passage rate of the food through the digestive tract. The daily digestible nitrogen intake was higher in hares Lepus europaeus than that in rabbits Oryctolagus cuniculus, indicating that hares compensated for their lower nitrogen digestibility. Hares were predicted to select for higher quality plant species in a natural situation, but they had, on average, a lower nitrogen and higher total fibre content in their diet compared to sympatrically occurring rabbits. This indicated that hares did not compensate for their lower digestive efficiency by selecting higher quality food plants. The present experiment shows that hares and rabbits have different digestive strategies to cope with low quality forage. Rabbits had a higher N-digestibility by increasing the retention time, whereas hares appeared to compensate for their lower N-digestibility by increasing the processing rate, when food quality deteriorated.

Pre-adult development time, dry weight at eclosion, and daily fecundity over the first 10 days of adult life were measured in five species of Drosophila from the melanogaster and immigrans species groups. Overall, the three species of the melanogaster group (D. melanogaster, D. ananassae, D. malerkotliana) developed faster, were lighter at eclosion, and produced more eggs per unit weight at eclosion than the two species of the immigrans group (D. n. nasuta, D. sulfurigaster neonasuta). The degree of sexual dimorphism in dry weight was greater than that in development time, but did not vary significantly among species, and was not correlated with fecundity, contrary to expectations that sexual selection for increased fecundity drives sexual size dimorphism in Drosophila. The degree of dimorphism in development time was significantly correlated with dry weight and fecundity, with lighter species tending to be more dimorphic for development time as well as more fecund, both in absolute terms and in terms of fecundity per unit weight. The results suggest that our understanding of the evolutionary forces maintaining sexual size dimorphism in Drosophila will probably benefit from more detailed studies on the correlates of sexual dimorphism within and among Drosophila species, and on the shape of reaction norms for the degree of sexual dimorphism across different levels of ecologically relevant environmental variables.

Many species of lizard use tail autotomy to escape from potential predators. While frequency of tail loss is an unreliable indicator of predation intensity it may enable inter-populational comparisons of predation costs. This reasoning was applied to a study of the metallic skink Niveoscincus metallicus. A total of 368 lizards was sampled from across four populations to compare the frequency and position of tail loss and ultimately to examine whether the implications of tail autotomy differ between populations. The overall frequency of tail loss was 72%, although between populations the incidence of tail autotomy varied from 61.4% (Laughing Jack Lagoon) to 78.2% (Dynnyrne). No sexual differences were observed in the frequency of tail loss; however, the incidence of autotomy increased with age. The estimated position of tail loss did not vary between the sexes, although individuals from Dynnyrne experienced more proximal tail breaks than the other populations. This resulted in the predicted energetic cost of tail loss being significantly higher in the Dynnyrne population and, when combined with a high frequency of tail loss and relatively smaller body size, suggests that this population incurs relatively high costs as a result of autotomy. Overall, measures of tail loss in N. metallicus were found to be useful for examining inter-populational variation in the cost of tail autotomy.

The behavioural response of the sleepy lizard Tiliqua rugosa to an extended drought was examined in spring and summer 2002. Observations of the behaviour and use of microhabitat by radio-tagged lizards for spring in 2000–2002 showed that the lizards in 2002 suffered decreased body mass and increased mortality, were less active, showed reduced mating behaviour and increased use of burrows when compared with the more normal wetter years of 2000 and 2001. The lizards lost significant mass owing to dehydration and starvation. An ‘onboard’ data logger recorded lizard stride frequency and body temperature continuously for 4 months on 11 lizards during the drought of 2002. The normally diurnal heliothermic sleepy lizards responded to rare rainfall events during the drought whenever they occurred, day or night, by emerging from burrows or other shelters for extended periods of activity with sub-optimal body temperatures as low as 8.5 °C. They moved more often, and with higher stride frequencies during periods of rain than during dry periods, both overnight and during the day. As a consequence of this extended activity under physiological stress, the lizards were able to respond to naturally occurring transient opportunities for food and water that would not have been available if they were only active at optimal body temperatures. In an area where freestanding water is rarely available, the lizards were able to access limited water by licking substrate. They also gained water and perhaps nutrition by consuming the temporarily rehydrated thalli of the free-living terrestrial cyanobacterium Nostoc commune. Such behaviour enabled lizards to regain much of the mass lost before the rainfall and probably enabled many lizards to survive until more normal food sources became available. These rare events may have a significant effect on the shaping of the sleepy lizards phenotypic capacities outside routine day-to-day activities.

Unique features of giraffe Giraffa camelopardalis anatomy are its long neck and slender long limbs. Its neck vertebrae should be light and have low density to make it manoeuvrable while the limb bones should have high density to provide the strength to support the giraffe's mass. Giraffes also have a very high vertical growth rate, a diet with a high Ca:P ratio, and a skeleton that constitutes a high proportion of its body mass. To investigate whether the giraffe skeleton is affected by its anatomy and biology, giraffe bone density and morphology were compared with those of African buffalo Syncerus caffer, an artiodactyl of similar mass, more conventional anatomy, a lower vertical growth rate, and different diet. Our results show that except for minor differences the density of giraffe bones is the same as that of buffaloes. Giraffe limb bones have a slightly greater diameter and much thicker walls than equivalent bones in buffaloes. Giraffe cervical vertebrae, unlike those in buffaloes, decrease in mass with cranial distance. We conclude that giraffe biology and anatomy do not affect bone deposition or density. However, other characteristics of their skeletons seem to be adaptations to their unique anatomy.

Pup mortality and the timing of birth of South American sea lions Otaria flavescens were investigated to determine the possible relationship between fluctuations in prey availability in the Peruvian upwelling ecosystem and current and future reproductive success of sea lions during six consecutive breeding seasons. Our study from 1997 to 2002 encompassed the strongest El Niño on record and one La Niña event. Pup mortality ranged from 13% before El Niño to 100% during El Niño, and was negatively correlated with prey availability. Abortions were also more frequent when prey availability was low. However, pup mortality remained high following El Niño due to the punctuated short-term effects it had on population dynamics and subsequent maternal behaviour. Births occurred later in the season after years of low food availability and earlier following years of high food availability. The peak of pupping occurred around the peak of mortality in all years, and may have been the product of intensive competition between bulls at the peak of the breeding season. The stronger and more frequent El Niños that appear to be occurring along the Peruvian coast may produce significant stochastic changes in future births and pup mortality, which may place the vulnerable South American sea lion population in Peru at greater risk.

If the energy-density of prey bodies is not uniform, predators usually should maximize their rate of energy intake while foraging by selectively consuming energy-rich regions of their prey and discarding other parts. In this study, the hypothesis of selective body-part consumption was tested using two species of dasyurid marsupials, Sminthopsis youngsoni and Ningaui ridei, and their invertebrate prey in arid central Australia. Energy-densities were similar for several divergent types of prey, including whole insects, centipedes, and spiders (20.2±2.19 (sd) J/mg ash-free dry mass), but there were marked differences in energy-density among orders of insects and also between different body regions of invertebrates. In captivity, the two dasyurid species consumed different body regions of prey in the same way. For beetles and cockroaches, the rank order for selection of body parts was abdomen, thorax, head, then legs; for centipedes it was body, then head + legs; and for spiders it was opisthosoma, prosoma and then legs. Selection of prey body regions by the marsupials correlated closely with the energy-densities of these regions, and also with the rates of energy intake that they yielded. In the field, selection of body parts of arthropod prey by dasyurids probably occurs primarily when prey is abundant. This selection should allow maximization of rates of energy intake in favourable periods and should, in turn, allow dasyurid predators to effectively exploit pulses of prey resources in the temporally variable desert environment.

Sperm competition is widespread, resulting in sexual selection when the gametes of two or more males compete for access to a given set of ova. This study shows, for the first time, that sexual selection has influenced the evolution of the mammalian vas deferens – that is, the muscular duct which rapidly transports spermatozoa from the cauda epididymis to the ampulla during sexual activity. Morphometric studies of 103 species, representing 70 genera of mammals, show that the vas deferens is on average 33% shorter and its muscular walls are 45% thicker, in those forms where sperm competition pressures are greatest. The outer and inner longitudinal muscle layers of the vas are thickened under these conditions, whereas the central, circular muscle layer is significantly reduced. Thus, mammals that have multiple partner mating systems, and large testes in relation to body weight, have shorter and more muscular vasa deferentia than mammals where single partner mating systems, and smaller relative testes sizes, are the norm. These differences are statistically significant after application of procedures to correct for possible phylogenetic biases in the data set. Sperm competition has played an important role in the evolution of the mammalian vasa deferentia, favouring muscular specializations that enhance sperm transport.

The genus Cryptomys contains a number of social, subterranean rodents that are widely distributed throughout sub-Saharan Africa. Specimens of Cryptomys from 23 localities in south-west Zambia were karyotyped using a standard staining protocol. A minimum of five metaphases per specimen was scored for 2n and the fundamental number (NF) was determined in females. Nine new karyotypes, which may represent several new species, were identified: (1) 2n=42, NF=78 (Dongo, Southern Province); (2) 2n=44, NF=76 (Salujinga, North-western Province); (3) 2n=45, NF=78 (Lochinvar, Southern Province); (4) 2n=52, NF=86 (Chinyingi, North-western Province); (5) 2n=54, NF=78 (Monze, Southern Province); (6) 2n=56, NF=76 (Watopa, North-western Province); (7) 2n=58, NF=80 (Livingstone, Southern Province); (8) 2n=58, NF=86 (Senanga, Western Province); (9) 2n=60, NF=82 (Kataba, Western Province; type locality of C. damarensis micklemi). Contrary to previous reports, the specimens from Kataba and Senanga on the left bank of the Zambezi do not correspond to C. damarensis and should be considered a separate species: C. micklemi (as confirmed by molecular analyses; Ingram, Burda & Honeycutt, 2004). According to the karyotype, C. damarensis occurs only on the right bank of the Zambezi River in the Western Province. In contrast to the high karyotypic variability on the right bank of the Kafue River, it was found that C. anselli (2n=68) is widely distributed throughout the Central province on the left bank of the Kafue River. The resulting pattern of occurrence of the different karyotypes correlates well with the extant river system configuration that separates most karyotypes. We hypothesize that geomorphological changes and in particular river system dynamics in recent geological times have played an important role in the chromosomal diversification and may have provided opportunities for speciation to occur.