Mehregan Ebrahimi

Mating behaviour in pygmy bluetongue lizards: do females ‘attract’ male lizards?

Abstract. Mating behaviour in lizards has been well studied, with most reports indicating that the male dominates in initiating the mating, characteristically displaying visually to attract partners. This strategy may be less successful in secretive species that remain in small areas around their refuge, infrequently encountering other conspecifics, like the endangered Australian pygmy bluetongue lizard (Tiliqua adelaidensis). Adult lizards of this species spend most of their time in or at the entrance of single-entrance vertical burrows, built by spiders, in patches of native grassland in South Australia. We filmed the behaviour of nine female lizards for 10 days in each month from October 2011 to February 2012. During filming in October, the austral spring, we observed 43 cases of females making moves away from their burrows, and back along the same path, in that month, that we did not observe among males, or among females in any other month. We observed 27 cases of males approaching female burrows, only in October and mostly along the paths previously taken by the females. Males attempted to mate, and were successful on five occasions. We describe the female movements and suggest that their function is to attract male mating partners.

Long and short term residence in refuge burrows by endangered pygmy bluetongue lizards

The pygmy bluetongue lizard ( Tiliqua adelaidensis) is an endangered species which is restricted to native grassland remnants in South Australia. Individuals live in vertical burrows with a single entrance from which they ambush invertebrate prey. We monitored marked burrows over two entire spring-summer seasons, the period when the lizards are active, and found that the population contained a mixture of dispersers that remained in a burrow briefly, and residents that occupy a burrow for the entire study period. There were more females than males among the residents and most of the burrow abandonment happened in the early spring, the time when male lizards probably move around to seek matings. Our study described burrow occupancy dynamics, and will assist the conservation management of this endangered species.

Lizard behaviour suggests a new design for artificial burrows

Abstract Context. The use of artificial refuges is a common strategy for the conservation management of endangered species. However, artificial refuges may alter an animal’s natural behaviour that in turn may be detrimental to the species. The endangered pygmy bluetongue lizard from Australia is one species that will accept artificial burrows. Aims. The aim of the present research was to determine whether the normal behaviour of the pygmy bluetongue lizards differed between artificial and natural burrows, so as to determine whether the existing artificial burrow is an optimal design for this species. Methods. In the present study, we filmed the behaviour of lizards as they entered artificial and natural burrows. We compared the number of times a lizard entered a burrow, the time that lizards spent inspecting burrows, and the behaviours that lizards used when entering artificial and natural burrows. Key results. We found that in natural burrows, lizards always entered head first, and then usually reversed direction inside, using an enlarged basal chamber, to sit with their head uppermost in the entrance. In artificial burrows, however, lizards had to enter head first, then reverse tail-first back out, and then reverse tail-first back into the burrow (so as to have their head facing upwards) We called this behaviour reversing from outside. Key conclusion. The stereotyped reversing-from-outside behaviour when entering artificial burrows, and its occasional occurrence in natural burrows, suggest that it has evolved to allow lizards to use narrow burrows as well as those with a chamber, even though it can increase lizard’s surface activity and exposure to predation. Implication. The reversing behaviour from outside the artificial burrow increases exposure to potential predators, and our observations suggest that a re-design of artificial burrows to incorporate internal space for turning around may improve their effectiveness in conservation management interventions.

Determining the success of varying short-term confinement time during simulated translocations of the endangered pygmy bluetongue lizard (Tiliqua adelaidensis)

Translocation is a powerful tool in conservation management, but one of the major problems of this tool is dispersal after release. Translocated animals might disperse from prime habitat and face unsuitable habitat and possible increased exposure to predators. This might lead to decline of a translocated population and could compromise the success of translocation. We assessed whether short-term confinement within enclosures at the translocation site can significantly decrease post release movement, if confinement allowed animals to become familiar with the new habitat, and to overcome handling related stress. We simulated the translocation of an Australian lizard, the endangered pygmy bluetongue lizard Tiliqua adelaidensis, into the centre of a large enclosure and compared the behaviour between individuals confined to the central region for one or five days before release. We found that lizards confined for five days spent less time basking, and were more likely to disperse than lizards confined for just one day. We suggest that short-term confinement of lizards induces additional stress and that extra days of short-term confinement will not necessarily improve the success of a translocation. Future research could determine the effectiveness of different durations of confinement for releasing animals at translocation sites.

Monitoring predation behaviour of the pygmy bluetongue lizard to decide when conservation intervention is needed

Abstract. Documenting natural behaviours may be an important component of conservation management of threatened species in that deviations from some behaviours may serve as early warning signs of subsequent deteriorating condition and the possible need for intervention. We described predation behaviour of the endangered Australian scincid lizard Tiliqua adelaidensis from 23 burrows by watching video images from cameras over 10 days each month for five months in spring and summer. We observed 341 predation attempts, of which 277 were successful. These lizards predominantly ambush passing prey from their burrow entrance without completely emerging from the burrow. Orthopterans were the major component of their captures; prey captures peaked in November and December. We measured the proportion of unsuccessful foraging attempts, the proportion of foraging attempts that involved full emergence, the mean distance a lizard moved away from the burrow entrance, and the proportion of plant parts in the diet. We suggest that if any of these parameters increase it could indicate the requirement for intervention management. Our study supports the view that behavioural monitoring could be considered as an integral component of any conservation management of endangered animal species.

A thirsty little lizard: drinking by the pygmy bluetongue lizard

ABSTRACT The pygmy bluetongue lizard (Tiliqua adelaidensis) is an endangered scincid lizard, endemic to the Mid North region of South Australia, where it occupies heavily fragmented patches of native grassland. Pygmy bluetongue lizards live in spider burrows and rarely venture far from their burrows. This limits their access to free standing water, and it was previously unknown whether lizards acquired all the water they needed from their food, or whether they could access an alternative source of water. This paper presents 27 observations of lizards drinking either from drops of morning dew or from rain drops accumulated on vegetation close to their burrow entrances. These observations suggest that pygmy bluetongue lizards can supplement their water requirements independent of free standing water sources, like streams or ponds, if there is vegetation that can collect dew and rain close to burrow entrances. Vegetation that can hold water droplets for a short time provides flexibility for the lizards in maintaining their water budgets. The water collecting function of vegetation should be included as a factor in short-term management decisions about the level of grazing in the lizard’s habitat. In the longer term, the benefits of having plants that can accumulate water drops will need to be considered if suitable relocation sites are to be found.

Short-term dispersal response of an endangered Australian lizard varies with time of year.

Dispersal is an important component in the demography of animal populations. Many animals show seasonal changes in their tendency to disperse, reflecting changes in resource availability, mating opportunities, or in population age structure at the time when new offspring enter the population. Understanding when and why dispersal occurs can be important for the management of endangered species. The pygmy bluetongue lizard is an endangered Australian species that occupies and defends single burrow refuges for extended periods of time, rarely moving far from the burrow entrance. However, previous pitfall trapping data have suggested movement of adult males in spring and of juveniles in autumn of each year. In the current study we compared behaviours of adult lizards each month, over the spring-summer activity period over two consecutive field seasons, to provide deeper understanding of the seasonal dispersal pattern. We released adult pygmy bluetongue lizards into a central area, provided with artificial burrows, within large enclosures, and monitored the behaviour and movements of the released lizards over a four day period. There was a consistent decline in time spent basking, amount of movement around burrow entrances, and rates of dispersal from the central release area from early spring to late summer. Results could be relevant to understanding and managing natural populations and for any translocation attempts of this endangered lizard species.

The ecological associations of surface-dwelling lizards in Qom Province in the Northwest of Central Plateau of Iran.

We used pitfall trapping to investigate the effects of elevation, plant density and soil structure on species diversity and the impact of these habitat factors on lizard habitat selectivity in the Qom Province in the Central Plateau of Iran. From a total of 12 1-ha plots, we captured 363 individuals of 15 species of lizards (six species of Lacertidae, five species of Agamidae, two species of Gekkonidae, one species of Varanidae and one species of Scincidae). A generalized linear model (GLM) determined that elevation was the most important factor impacting species diversity. The highest species diversity was at the intermediate elevation (1289 m). Abundance of 6 out of 15 species showed strong relationships with some habitat factors. These relationships were demonstrated by habitat selectivity index (Ivlevs index). Our result supports other surveys that showed that elevation plays an important role in determining lizard species diversity.

Embryonic and early development of the Zagros tooth‐carp, Aphanius vladykovi (Actinopterygii: Cyprinodontidae)

The embryonic and early larval development of laboratory reared Zagros tooth‐carp, Aphanius vladykovi Coad, 1988, are described and illustrated. Development and embryogenesis start with the external fertilization of sticky, transparent and spherical telolecithal/macrolecithal eggs with a mean diameter of 1.61± 0.12 mm and it continues with meroblastic/radial cleavage, blastulation/blastula formation, epibolic cell migration during gastrulation and organogenesis resulting in a newly hatched larvae of 5.23 ± 0.09 mm in length with attached yolk sac at about 164 hr (at 24 ± 1°C) after fertilization.

Interactions between pygmy bluetongue lizards and co-existing species

This article describes observations of interactions between endangered pygmy bluetongue lizards (Tiliquaadelaidensis) and other species that co-occur in their native grassland habitat in the mid-north region of South Australia. The lizard lives in spider burrows, and rarely moves away from the burrow entrance. We viewed over 16,000 h of video recording of occupied pygmy bluetongue lizard burrows, taken over five 10-day periods throughout one complete lizard activity season, and documented all cases in which these endangered lizards interacted with co-existing species. We found that these interactions were infrequent. We observed potential competition over burrow resources with lycosid spiders (Lycosaspp), centipedes, and a house mouse, and potential competition over invertebrate prey with a predatory wasp. We also observed unsuccessful predation attempts on lizards in burrows by ravens and brown snakes. We suggest that conservation management might have proceeded effectively without this information, but that it provides useful background information for informed decision making.