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C. Michael Bull - One of the best experts on this subject based on the ideXlab platform.
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A nose for Lizards; can a detection dog locate the endangered pygmy bluetongue Lizard (Tiliqua adelaidensis)?
Transactions of The Royal Society of South Australia, 2016Co-Authors: Torben P. Nielsen, Gary Jackson, C. Michael BullAbstract:ABSTRACTEnvironmental detection dogs have been used in various research and conservation projects. By detecting scent, dogs are capable of finding animals or scats that are virtually undetectable to humans. The endangered pygmy bluetongue Lizard (Tiliqua adelaidensis) is endemic to heavily fragmented patches of native grassland in the mid-north region of South Australia. The Lizards live in spider burrows with entrance diameters of 10–20 mm, which makes them difficult to find. This study presents the first data showing that a dog can detect pygmy bluetongue Lizards. The dog showed the ability to distinguish between pygmy bluetongue Lizard scent and the scent of sleepy Lizard (Tiliqua rugosa) and bearded dragon (Pogona barbata). The dog also found more than 30 occupied Lizard burrows in the field. Up until now surveys of this endangered Lizard have relied on human visual detection of burrows, which is a very labour-intensive process. Although the climate and the ecology of the Lizards pose a challenge to d...
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A thirsty little Lizard: drinking by the pygmy bluetongue Lizard
Transactions of The Royal Society of South Australia, 2015Co-Authors: Torben P. Nielsen, Mehregan Ebrahimi, C. Michael BullAbstract:ABSTRACTThe 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 mai...
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Responses of the endangered pygmy bluetongue Lizard to conspecific scats
Journal of Ethology, 2011Co-Authors: Aaron L. Fenner, C. Michael BullAbstract:Many animals use chemical signals for communication between conspecifics and for territory marking. The pygmy bluetongue Lizard is normally solitary, focussing activity around the entrance of its burrow, from where it ambushes prey, and rarely contacts other individuals. In this paper we examined whether Lizards in laboratory experiments alter their behaviour in the presence of scats from conspecifics. In the first experiment, when Lizards were offered a choice of two vacant burrows with or without a scat close to the entrance, they tongue flicked more often at the burrow entrance when the scat was present, and more often chose to occupy the burrow with the scat. An interpretation is that Lizards use scat signals to recognise burrows that may be suitable because they have previously been occupied by a conspecific, but that they approach those burrows cautiously in case a resident is still present and likely to resist a takeover. Scats from male Lizards were inspected (by both sexes) for longer than scats of female Lizards. In the second experiment, when resident Lizards were presented with scats outside of their burrows, they inspected and tongue flicked at those scats more often if the scat came from a male than a female Lizard, but there was no definitive evidence from our experiments that Lizards differentiated in their response to scats from Lizards that were found close to or far from the test Lizard. The results were consistent with a communication system in which Lizards use scats to advertise their presence, independent of any direct contact.
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Non-invasive Lizard identification using signature curves
TENCON 2009 - 2009 IEEE Region 10 Conference, 2009Co-Authors: Damian Tohl, Sharmil Randhawa, Leili Shamimi, C. Michael BullAbstract:A novel non-invasive method is proposed to help identify the endangered Pygmy Bluetongue Lizard. This would be preferable to the commonly used, invasive, toe-clipping method, which could be unreliable if the Lizard was to lose a toe or foot naturally. Each Lizard has a unique and permanent scale pattern which can be used to identify individual Lizards. The proposed method involves a novel technique to derive a signature curve from the Hough transform output of the Lizard scale pattern such that the signature curve is scale and shift invariant. It has been found that a Lizard can be successfully identified by comparing its signature curve with those signature curves of all registered Lizards stored in a database.
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Interactions between climate, host refuge use, and tick population dynamics
Parasitology Research, 2006Co-Authors: Gregory D. Kerr, C. Michael BullAbstract:The relationship between Australian sleepy Lizard ( Tiliqua rugosa ) microhabitat use and tick ( Amblyomma limbatum ) population dynamics was investigated. Over 3 years (2002–2004) between 23 and 50 Lizards were radio-tracked up to four times a week to record microhabitat use and each fortnight to determine tick loads. Daily maximum temperature was highly predictive of Lizard microhabitat use. In hotter fortnights Lizards used larger bushes and burrows for refuge. Peak background tick infestation levels and pulses of attachment coincided with higher ambient temperature. Male ticks attached throughout the year independent of season. Engorged females detached late in spring, summer and autumn, when climate regularly restricted Lizards to a few thermally conservative refuges. Peak nymph and larval attachment occurred over summer and into autumn. Climate-dependent timing and type of host refuge use may influence tick population density. In more temperate summers Lizards may avoid refuges with potentially high parasite loads.
Piotr Tryjanowski - One of the best experts on this subject based on the ideXlab platform.
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Do males pay more? A male-biased predation of common Lizard (Zootoca vivipara) by great grey shrike (Lanius excubitor)
acta ethologica, 2019Co-Authors: Marcin Antczak, Viktória Majláthová, Igor Majláth, Martin Hromada, Anna Ekner-grzyb, Martin Bona, Piotr TryjanowskiAbstract:Predation is one of the most important factors affecting biology, ecology and behaviour of the prey. We have studied predation of the common Lizard ( Zootoca vivipara ) by the great grey shrike ( Lanius excubitor ) in farmland habitats in western Poland. Shrike caches were used as a source of information about preyed Lizards. Shrikes hunt significantly more adult males than females, juveniles and sub-adults; the pattern was similar over all three study years. Male Lizard had longer activity time than female; therefore, they seem to be under predation pressure for a longer time during breeding season. Capture and count transect data of common Lizard populations living within and outside shrike territories showed significant seasonal differences: within shrike territories, there was lower proportion of males than females; moreover, in some territories, the number of males in the Lizard population was negatively correlated with the number of males impaled by shrikes. Our findings suggest that in this particular predator-prey system, shrikes may be a strong selective force for Lizards’ population dynamics. Male-biased predation could be caused by differences in the behaviour of adult male and female Lizards, namely longer activity of males and differences in space and refuge use.
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Blood parasites in two co-existing species of Lizards (Zootoca vivipara and Lacerta agilis)
Parasitology Research, 2010Co-Authors: Viktória Majláthová, Igor Majláth, Božena Haklová, Martin Hromada, Anna Ekner, Marcin Antczak, Piotr TryjanowskiAbstract:We investigated the occurrence of blood parasites of two Lizard species: the common or viviparous Lizard ( Zootoca vivipara ) and the sand Lizard ( Lacerta agilis ) in western Poland. Selected traits of Lizard body morphology were studied with respect to the presence and intensity of haematozoan infection in blood samples collected from 218 adult Lizards; 88 of the common Lizard and 130 of the sand Lizard. Haemogregarinid blood parasites were found to be the common parasite of both Lizard species in studied locality with prevalence 39.8 (95% CL, 29.5–50.8) for Z. vivipara and 22.3 (95% CL, 15.5–30.4) for L. agilis . Incidence of parasitemia did not differ between sexes and was not correlated with morphological traits or presence of ectoparasites— Ixodes ricinus ticks. However, a significant difference between the two species of Lizards was a greater frequency of haemogregarinid parasitism in Z. vivipara .
Jose Martin - One of the best experts on this subject based on the ideXlab platform.
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lipophilic compounds in femoral secretions of male collared Lizards crotaphytus bicinctores iguania crotaphytidae
Biochemical Systematics and Ecology, 2013Co-Authors: Jose Martin, Jesus Ortega, Pilar LopezAbstract:Abstract In many Lizards, chemical compounds from the femoral gland secretions are used in intraspecific communication, but most studies describing these chemicals are for Lizard species included in the Scleroglossa clade, whereas Lizards within the Iguanian clade have been much less studied, probably because these Lizards were considered to rely more on visual cues. However, many iguanian Lizards have abundant femoral secretions and are able of chemosensory conspecific recognition, which might be based on compounds secreted by femoral glands. By using GC–MS analyses, we found 58 lipophilic compounds in femoral gland secretions of male Great Basin collared Lizard, Crotaphytus bicinctores (Iguania, Crotaphytidae). Main compounds were steroids (mainly two triunsaturated steroids and cholesterol), carboxylic acids (mainly hexadecanoic acid), waxy esters of long chain fatty acids, alcohols (mainly hexadecanol), aldehydes and other minor compounds. We compared these compounds with those found in other Lizard species and discussed the potential signaling function of some compounds and how the xeric habitat of this Lizard could have conditioned the composition of secretions.
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Interpopulational variation in chemosensory responses to selected steroids from femoral secretions of male Lizards, Podarcis hispanica, mirrors population differences in chemical signals
Chemoecology, 2012Co-Authors: Marianne Gabirot, Pilar Lopez, Jose MartinAbstract:Chemical signals are important for mate and species recognition. If variation in chemical signals occurs between populations of the same species, these differences could later preclude mating between populations and lead to speciation. In the Iberian wall Lizard, Podarcis hispanica , the lipophilic fraction of femoral secretions of males is mainly a mix of steroids and fatty acids. Among steroids, the most abundant compounds are cholesterol and cholesta-5,7-dien-3-ol, which are implicated in intraspecific communication and sexual selection. Interpopulational differences in chemical signals of males, and in response to these chemicals, could contribute to reproductive isolation between populations, which would explain the known genetic differences between these populations. Chemical analyses indicated that five distinct populations of this Lizard from Madrid (Central Spain) differed in the proportions of two steroids (cholesterol and cholesta-5,7-dien-3-ol) in femoral secretions. Moreover, Lizards discriminated and had high chemosensory responses (i.e., high tongue-flick rates) to these steroids, but showed interpopulational differences. Lizards from populations with cold temperatures and high relative humidity (i.e., northern Madrid) elicited higher responses to these steroids, whereas the converse occurred for Lizards from populations occupying dry and hot habitats (i.e., southern Madrid). Interestingly, the magnitude of the chemosensory responses to cholesta-5,7-dien-3-ol in each population mirrored the abundance of this compound in secretions of males of that population. These results suggest that the importance of cholesta-5,7-dien-3-ol in males’ secretions might be lower for Lizards from the southern populations. These differences in the relative importance of chemical signals could explain reproductive isolation and cryptic speciation between populations of this Lizard.
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Iberian Rock Lizards (Lacerta monticola cyreni) Assess Conspecific Information Using Composite Signals from Faecal Pellets
Ethology, 2010Co-Authors: Pilar Lopez, Pedro Aragón, Jose MartinAbstract:A field and laboratory study was performed to analyse the role of excrement deposited on the substrate in intraspecific communication of the Iberian rock-Lizard (Lacerla monticola cyreni). In the field, Lizards selected specific sites on rocks to deposit faecal pellets, probably in order to facilitate visual location of pellets by conspecifics. Differential tongue flick rates to chemicals presented on cotton swabs demonstrated that male Lizards can detect and discriminate between self-produced scents from faecal pellets and those of other conspecific males. In a subsequent experiment, male Lizards were tested in a chamber with two platforms containing a faecal pellet of other male on one side and a control artificial pellet on the opposite side. Males spent significantly less time on the side containing the faecal pellet, suggesting that the decision of where to stay may depend on the presence of faecal pellets. Smaller males moved less than larger males on the experimental side whereas on the control side body size did not influence the proportion of time moving. The ability to discriminate chemicals from faeces, and the effects of faecal pellets on Lizard behaviour, suggests that faeces might act as composite signals (visual and chemical) in the intraspecific communication of this Lizard.
J. Martin - One of the best experts on this subject based on the ideXlab platform.
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Prevalence and intensity of haemogregarinid blood parasites in a population of the Iberian rock Lizard, Lacerta monticola
Parasitology Research, 2004Co-Authors: P. López, J. MartinAbstract:The study of the effect of parasites on their host populations is essential for understanding their role in host population dynamics and ecology. We describe the general field population biology of haemogregarines in the Iberian rock Lizard, Lacerta monticola , examining the factors that determine the prevalence and intensity of infection. Prevalence and infection intensity were higher in adults than in juvenile Lizards. The prevalence rate was higher in larger Lizards, probably because they were also older and had been more often in contact with parasites during their lifetime. During the mating season, the intensity of parasite infection was greater in males than in females, probably due to immunosuppressive effects of testosterone. The parasite load had a negative effect on the body condition during the reproductive season. The results suggest that the interactions between parasites and hosts are not stable in this Lizard population.
Viktória Majláthová - One of the best experts on this subject based on the ideXlab platform.
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Do males pay more? A male-biased predation of common Lizard (Zootoca vivipara) by great grey shrike (Lanius excubitor)
acta ethologica, 2019Co-Authors: Marcin Antczak, Viktória Majláthová, Igor Majláth, Martin Hromada, Anna Ekner-grzyb, Martin Bona, Piotr TryjanowskiAbstract:Predation is one of the most important factors affecting biology, ecology and behaviour of the prey. We have studied predation of the common Lizard ( Zootoca vivipara ) by the great grey shrike ( Lanius excubitor ) in farmland habitats in western Poland. Shrike caches were used as a source of information about preyed Lizards. Shrikes hunt significantly more adult males than females, juveniles and sub-adults; the pattern was similar over all three study years. Male Lizard had longer activity time than female; therefore, they seem to be under predation pressure for a longer time during breeding season. Capture and count transect data of common Lizard populations living within and outside shrike territories showed significant seasonal differences: within shrike territories, there was lower proportion of males than females; moreover, in some territories, the number of males in the Lizard population was negatively correlated with the number of males impaled by shrikes. Our findings suggest that in this particular predator-prey system, shrikes may be a strong selective force for Lizards’ population dynamics. Male-biased predation could be caused by differences in the behaviour of adult male and female Lizards, namely longer activity of males and differences in space and refuge use.
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Blood parasites in two co-existing species of Lizards (Zootoca vivipara and Lacerta agilis)
Parasitology Research, 2010Co-Authors: Viktória Majláthová, Igor Majláth, Božena Haklová, Martin Hromada, Anna Ekner, Marcin Antczak, Piotr TryjanowskiAbstract:We investigated the occurrence of blood parasites of two Lizard species: the common or viviparous Lizard ( Zootoca vivipara ) and the sand Lizard ( Lacerta agilis ) in western Poland. Selected traits of Lizard body morphology were studied with respect to the presence and intensity of haematozoan infection in blood samples collected from 218 adult Lizards; 88 of the common Lizard and 130 of the sand Lizard. Haemogregarinid blood parasites were found to be the common parasite of both Lizard species in studied locality with prevalence 39.8 (95% CL, 29.5–50.8) for Z. vivipara and 22.3 (95% CL, 15.5–30.4) for L. agilis . Incidence of parasitemia did not differ between sexes and was not correlated with morphological traits or presence of ectoparasites— Ixodes ricinus ticks. However, a significant difference between the two species of Lizards was a greater frequency of haemogregarinid parasitism in Z. vivipara .
