Agonistic and mating behaviour of the endemic lizard Trachylepis atlantica from the Fernando de Noronha archipelago, Brazil

The skink Trachylepis atlantica is endemic to the Fernando de Noronha archipelago. Although this species is abundant in the archipelago, it is increasingly threatened by invasive species, predation, and anthropic interference. However, little is known about its natural history. Here we report on territory use, male-male combat, and mating behaviour of freeranging T. atlantica. During the dry season, we observed two bouts of male combat and two copulations, which suggests some mating seasonality. In male combat, T. atlantica displays ritualised agonistic behaviour with escalated aggressiveness that include - i) visualisation, approaching or following, ii) visual display, iii) bite and body confrontation, and iv) dominance. Adult males were always alert to invaders within their territories. After combat, resident males showed scars on their heads resulting from agonistic encounters. During the two copulations, we observed courtship, immobilisation, and mating.

Levels of testosterone, progesterone and oestradiol in pregnant-lactating does in relation to aggression during group housing

The neuroendocrine regulation of rabbit maternal behaviour has been explored in detail. However, little is yet known about the hormonal regulation of aggression in concurrently pregnant-lactating does, a reproductive condition that prevails during group housing of rabbits on farms. Therefore, in this study we determined the relation between a) the levels of progesterone, testosterone, and oestradiol during lactation; b) the anogenital distance at artificial insemination; and c) the timing of grouping with the intensity of agonistic behaviour, published previously. We performed four consecutive trials, where three groups of eight does each were artificially inseminated on day 10 postpartum (pp) and grouped on either day 12, 18 or 22 pp. Using Dipetalogaster maxima, a reduviid blood-sucking bug, we collected blood samples during the pregnant-lactating phase (days 13, 15, 17, 19, 21, 23 pp) on one or two randomly chosen does per treatment group. Testosterone levels varied little across the pregnant-lactating phase, agreeing with results from pregnant-only rabbits, while progesterone levels increased from day 3 (=13 dpp) to day 7 (=17 dpp) and remained unchanged until day 13 (=23 dpp) of pregnancy. All oestradiol concentrations fell below the limit of detection. Overall, all concentrations were slightly lower in comparison to rabbit studies with pregnantonly does. The agonistic behaviour was not related to the respective hormonal concentrations at grouping. In conclusion, the time point of grouping does after artificial insemination (AI) in the semi-group housing system only had a weak influence on aggression and the hormonal profile did not indicate an optimum time for grouping.

A new ankylosaurid from the Upper Cretaceous Nemegt Formation of Mongolia and implications for paleoecology of armoured dinosaurs

A new ankylosaurid dinosaur, Tarchia tumanovae sp. nov., has been recovered from the Upper Cretaceous Nemegt Formation of Mongolia. It includes a well-preserved skull, dorsal, sacral, caudal vertebrae, sixteen dorsal ribs, ilia, a partial ischium, free osteoderms, and a tail club. The squamosal horns of T. tumanovae are divided into two layers, the external dermal layer and the underlying squamosal horn proper. The irregular ventral margin of the base of the upper dermal layer may represent a resorption surface, suggesting that the squamosal horns of some ankylosaurids underwent extreme ontogenetic remodeling. Localized pathologies on the dorsosacral ribs and the tail provide evidence of agonistic behaviour. The tail club knob asymmetry of T. tumanovae resulted from restricted bone growth due to tail club strikes. Furthermore, T. tumanovae had an anteriorly protruded shovel-shaped beak, which is a morphological character of selective feeders. Ankylosaurid diets shifted from low-level bulk feeding to selective feeding during the Baruungoyot and the Nemegt “age” (middle Campanian-lower Maastrichtian). This ankylosaurid niche shifting might have been a response to habitat change and competition with other bulk-feeding herbivores.

Interspecific agonistic behaviour of Odontotermes javanicus and Microcerotermes sp. (Isoptera: Termitidae): Preliminary study

Termite interaction from the same or different colonies or species can display a variety of agonistic behaviours. The study aimed to observe the interspecific agonistic behaviour of Odontotermes javanicus and Microcerotermes sp. For this purpose, an assay was carried out using a test arena separated into two groups. Termite responses were tested against each other in the following pairwise test (worker versus worker, worker versus soldier, and soldier versus soldier) with a 1:1 ratio (ten individuals) from each colony. Specimens were collected at the area of Forestry Faculty, Universitas Hasanuddin, Indonesia. The observed agonistic behaviour of both species is dominated by examination (antennation) and aggression (attacking, grappling, and biting). There were three treatment combinations that classified as no aggression, except for the treatment (Microcerotermes sp. soldier versus O. javanicus worker) that classified in aggression level 3 (aggressive). Based on termite survival after five minutes of testing, O. javanicus is more competitive than Microcerotermes sp,; no more individual termites of both species survive after 24 hours of testing.

Monitoring Behaviour in African Elephants during Introduction into a New Group: Differences between Related and Unrelated Animals

The introduction of elephants into new groups is necessary for breeding programmes. However, behavioural studies on the reactions of these animals at first encounters are missing. In the present study, female African elephants (Loxodonta africana) living in zoos were observed during unifications with unfamiliar elephants (introduction of two to one females and one to two females; n = 6) and reunifications with related elephants (two mother–daughter-pairs; n = 4) that were separated for 2 and 12 years, respectively. First encounters of the elephants were observed and recorded by scan sampling. The parameters measured were (a) signs of the characteristic Greeting Ceremony, (b) distance to the fence separating the elephants during first contact, and (c) time until trunks touched for the first time. The data were statistically analysed with SPSS. The results showed that related elephants performed a full Greeting Ceremony on reunifications. Unrelated elephants only expressed a minor greeting. During first encounters, related elephants predominantly showed affiliative behaviour (p = 0.001), whilst unrelated elephants expressed more agonistic behaviour (p = 0.001). The distance to the fence was significantly smaller for related elephants than for unrelated elephants (p = 0.038). first contact of trunks occurred on average after 3.00 s. in related elephants and 1026.25 s. in unrelated elephants. These findings indicate that related elephants recognise their kin after up to 12 years of separation, meet them with a full Greeting Ceremony during reunification, and seek contact to the related elephant, while unrelated elephants are hesitant during unifications with unfamiliar elephants and express more agonistic behaviour. The results testify that zoo elephants show the same species-specific social behaviour as their conspecifics in the wild. It also confirms the cognitive abilities of elephants and the significance of matrilines for breeding programmes.

Opposing effects of dopamine on agonistic behaviour in crayfish

The effects of dopamine on the agonistic behaviour of crayfish were analysed. When dopamine concentrations of 1 µM were injected into large crayfish, individuals were beaten by smaller opponents, despite their physical advantage. Injection of 10 µM dopamine into small animals increased their winning rate against larger opponents. The inhibitory effect of dopamine on larger animals would be mediated by D1 receptors, and the injection of D1 receptor antagonist prohibited the onset of a loser effect in subordinate animals. The facilitating effect of dopamine on small animals would be mediated by D2 receptors, and the injection of D2 receptor antagonist prohibited the onset of a winner effect in dominant animals. Since the inhibitory effect of 1 µM dopamine was similar to 1 µM octopamine and the facilitating effect of 10 µM dopamine was similar to 1 µM serotonin, functional interactions among dopamine, octopamine, and serotonin were analyzed by co-injection of amines with their receptor antagonists in various combinations. The inhibitory effect of 1 µM dopamine disappeared when administered with D1 receptor antagonist, but remained when combined with octopamine receptor antagonist. Octopamine effects disappeared when administered with either D1 receptor antagonist or octopamine receptor antagonist, suggesting the dopamine system was downstream of octopamine. The facilitating effect of 10 µM dopamine disappeared when combined with serotonin 5HT1 receptor antagonist, as well as D2 receptor antagonist. Serotonin effects also disappeared when combined with D2 receptor antagonist, suggesting that dopamine and serotonin activated each other through mutual parallel pathways.