In species of many taxa, males alter their investment in ejaculates depending on perceived levels of male–male competition and female mating history/age. Males of the tettigoniid Acanthoplus discoidalis produce a large sperm ampulla and associated spermatophylax, resulting in a long refractory period for males. Female A. discoidalis mate once before laying eggs, and then mate and lay eggs in a random order. The males, therefore, only have a high confidence of paternity when mating with virgins. Male A. discoidalis were studied to determine if they alter their investment in sperm count, spermatophylax mass and water content of spermatophylaces when mating with virgin and non-virgin females. No difference in investment in any spermatophore characteristics between virgins and non-virgins was found, but males do reject non-virgins more often, preferring to transfer spermatophores to virgin females. Males seem to prefer females of a lower mass, where higher mass may reflect increasing female age (and hence likelihood of previous matings) through advanced development of eggs. Outright rejection, rather than changes in spermatophore investment may be because of constraints in tailoring large spermatophores that develop over relatively long periods of time between matings.

In ungulates, a set of deciduous teeth is replaced by a set of permanent teeth during their first 2 years of life. Little is known about factors causing variation in timing of tooth eruption, but overall size, condition or mineral deficiencies may play a role. The pattern of incisor (I) and canine (C) eruption was investigated in 2241 yearlings from five populations of red deer Cervus elaphus in Norway during 1964–2001. Before the sampling period (10 September–15 November), I1 had erupted in most yearlings (97%), while eruption of I3 and C had barely started (erupted in 7% and 5% of individuals, respectively). Exactly 50% of the yearlings had erupted I2. Jawbone length was shown to be a main determining factor for eruption of I2. However, for a given jawbone length, there was large variation among populations in the proportion of yearlings with erupted I2 (from <20% to >75%). Females got their permanent I2 earlier than males. Tooth eruption was found to be later with increasing local deer density, even after correcting for body weight. There was a residual effect of body weight (a measure of condition) after body size (measured as jawbone length) was controlled for in one of five populations, indicating that overall condition may influence timing of tooth eruption in this area. There was no evidence that calcium was limiting for eruption, as no correlation was found between timing of eruption and limestone in bedrock. Since there is large variation in timing of tooth eruption among red deer populations even after controlling for differences in phenotype and environmental factors, genotypic variation may also play an important role for tooth eruption patterns.

To determine the effects of their movement patterns, seven Cape clawless otters Aonyx capensis were caught in two rivers and radio-tracked between 1993 and 1995. Total range length varied from 4.9 to 54.1 km and core length from 0.2 to 9.8 km. Total area of water used varied between 4.9 and 1062.5 ha, and core areas from 1.1 to 138.9 ha. As predicted using the resource dispersion hypothesis, total home-range length was correlated with mean reed bed (high food density patch) nearest neighbour distance. The pattern of home-range use by females was suggestive of territoriality. Male Cape clawless otters had overlapping home ranges, both with other males and with females.

Recent advances in molecular scatology have allowed the development of reliable and non-invasive methods that can be applied in monitoring of small carnivores, without disturbance of the animals. Here a method is described that can be used to differentiate European mink Mustela lutreola, polecat M. putorius and American mink M. vison based on the analysis of DNA extracted from faeces. It consists of a nested PCR of a region of the mitochondrial D-loop followed by digestion of the resulting 240 bp amplicons with the restriction enzymes RsaI and MspI. The restriction patterns of both enzymes, when used together, are found to detect species-specific sequence variation. Two different haplotypes for European mink (AA, AB), another two for the polecat (AC, AD) and one for American mink (BC) can also be discriminated by this technique. Two new haplotypes for the mitocondrial D-loop of mustelids are described after DNA sequencing.

Four species of canids occur in the Cerrado of central Brazil. Three of them, the maned wolf Chrysocyon brachyurus, the crab-eating fox Dusicyon thous and the hoary fox Dusicyon vetulus, were studied in Emas National Park between 1996 and 1999 to investigate niche separation. The diet of the three species was studied to understand niche breadth and degree of overlap. Habitat and activity patterns were used as second and third ecological parameters to define niche dimensions, and were estimated using camera-trap data. The maned wolf is the largest species, weighing c. 21 kg, and is about three times larger than the crab-eating fox and six times larger than the hoary fox. The major ecological differences between the three species were found in their food niche and habitat use, where crab-eating fox presented higher differences from the hoary fox (Pianka's index of niche overlap (O) = 0.405). Despite differences in niche breadth, habitat use between the hoary fox and the maned wolf were more similar, explaining their larger overlap, in comparison with habitat use by the crab-eating fox. Activity patterns among the species showed less divergence. The three species presented two activity peaks, one in the dusk–night period and another in the morning period. These data permit a better understanding of the ecological separation of the three Cerrado canids that enables their coexistence.

The asymmetric male and female genitalia of the spider Metagonia mariguitarensis (González-Sponga) are described, based on semi-thin serial sections and SEM photographs, and several male genital and non-genital characters are measured and analysed statistically. Left male genital bulbs are significantly larger than right bulbs while right palpal tibiae are significantly stronger than left tibiae, suggesting a functional segregation into a more predominantly displaying right palp and a more predominantly sperm-transferring left palp. Despite several structural differences between right and left male palps, however, there is no indication of qualitative differences: both bulbs transfer sperm, and both palps are provided with a full set of muscles. The female internal genitalia are provided with an unpaired receptacle that is connected to the uterus externus by a wide and complicated duct and to the valve separating uterus externus from uterus internus by a short narrow duct. This resembles entelegyne genitalia, but the functional details remain unknown. The evolution of asymmetric genitalia is discussed in a wider framework, with the conclusion that the causes of asymmetry in spiders may be different from those in other arthropods such as insects and copepods.