Rainbow Lizard Research Articles

The costs of living in the city: influence of urbanization on the trophic niche and body condition of the African rainbow lizard Agama picticauda

The costs of living in the city: influence of urbanization on the trophic niche and body condition of the African rainbow lizard Agama picticauda

Diversity and Composition of Gastrointestinal Helminths and Gram-Negative Bacteria of the West African Rainbow Lizard (Agama picticauda) in a Human-Modified Landscape: Implications for Conservation and Zoonosis

Emerging infectious diseases are negatively impacting herpetofaunal populations globally, posing a major conservation threat. Anthropogenic perturbations of natural habitats may influence wildlife disease dynamics and spillover events. Although viral and fungal diseases of vertebrates have received considerable studies, there is scant information on the enteric bacteria and helminths of herpetofauna. Here, we assessed the gastrointestinal helminths and Gram-negative bacteria of the West African rainbow lizard (Agama picticauda) in a human-dominated landscape in Accra, Ghana. We used the flotation method and standard cultural, morphological, and biochemical methods, for helminths and bacteria, respectively. Four helminth species, Ascaris spp., Enterobius spp., Pharyngodon spp., and Oxyurid spp., were identified, with overall high (71.9%) prevalence. Ascaris spp. (χ2 = 33.33, p < 0.001 ) and Pharyngodon spp. (χ2 = 14.5, p < 0.001 ) were more prevalent in suburban lizards during the wet season than dry season. The prevalence of Ascaris spp. and Enterobius spp. was significantly higher (χ2 = 12.34, p < 0.001 ) in urban than suburban lizards, while Oxyurid spp. was more prevalent (χ2 = 4.75, p = 0.03 ) in the suburban lizards during the wet season. The gut bacteria identified (prevalence) were Escherichia spp. (86.5%), Enterobacter spp. (75.7%), Proteus spp. (67.6%), Shigella spp. (40.5%), Klebsiella spp. (21.6%), and Salmonella spp. (16.2%). The prevalence of Escherichia spp. and Proteus spp. was significantly higher (χ2 = 5.77–7.34, p = 0.01 – 0.02 ) in suburban lizards than urban lizards during the wet season. Some Ascaris spp., Enterobius spp., Escherichia spp., Enterobacter spp., Shigella spp., and Salmonella spp. are found in humans. Our data can serve as baseline information for long-term monitoring studies of reptile-parasites-environment interactions in the Accra plains of Ghana. Further studies using molecular techniques are needed to ascertain the zoonotic helminths and bacteria of A. picticauda.

Opportunistic foraging strategy of rainbow lizards at a seaside resort in Togo

AbstractRainbow lizards (Agama agama) are common in suburban areas throughout Africa, and have an opportunistic foraging strategy, with arthropods being the main prey source. In a coastal resort in southern Togo, West Africa, several individuals in a population were observed while feeding regularly upon non‐natural human‐made food (pizza) and showing a clear preference for a given type of food versus others that were offered (‘four cheeses’ being the preferred one). The fact that all monitored individuals fed upon a same type of pizza suggests that they may have some chemical cues attracting them.

From diurnal to nocturnal activity: a case study of night-light niche expansion in Agama agama lizards

Most species of lizard are either diurnal or nocturnal, and it is extremely rare to find species that operate both diurnally and nocturnally, or that may shift from diurnality to partial nocturnality when conditions allow. However, niche expansion from diurnal to nocturnal habits (often referred to as the night-light niche) has rarely been reported in lizards (mainly in Anoles), and mostly through anecdotal reports. In West Africa, the rainbow lizard Agama agama is a conspicuous species across the region but also lives in suburban areas of towns and villages. It is a diurnal sun-basker operating at relatively high body temperatures of 36 °C and higher. In this paper, we describe a night-light niche expansion, i.e. nocturnal foraging and thermoregulation, in a small number of A. agama populations living in suburban areas. These lizards utilised radiant heat from incandescent light bulbs situated on the walls of buildings to mostly achieve target body temperatures and forage for and fed on five different groups of invertebrates. Foraging lizards had significantly higher body temperatures than inactive lizards. However, variance in body temperature was significantly greater in foraging lizards than in inactive lizards probably due to the necessity to shuttle between the incandescent night lights and cooler foraging areas during activity, a known cost of thermoregulation. Regression analysis of body temperatures against time of night in foraging lizards supported the notion that the lizards were maintaining body temperatures by actively thermoregulating whilst in inactive non-basking resting lizards during the same time period body temperatures declined. Although our results indicate a potential thermoregulatory benefit from using the night-light shift, we cannot be certain that this benefit is the direct cause of the shift, rather than an additional advantage when foraging.

Endo-Helminth Fauna of the Rainbow Lizard (Agama Agama)

This parasitological study was carried out between February and May 2019 to determine the prevalence and intensity of helminthiasis in the rainbow lizard (Agama agama) in Okrika, Rivers State, Nigeria. A total of one hundred and fifty-one (151) specimens made up of 93 males and 75 females were caught by a local netting system during the day and anaesthesized with chloroform. Samples were collected from two stations (Ogoloma-Ama and Oba-Ama). After dissection, the esophagus, stomach, small intestine, rectum, liver, lungs, urinary bladder, heart and body cavity were searched for helminths using conventional methods. Five species of helminths belonging to Nematoda - Strongyluris brevicaudata, Parapharyngodon awokoyai, encysted Ascaridida larva, Cestoda - Oochoristica sp. and Trematoda - Mesocoelium spp - were recovered from infected lizards. Helminths infected one hundred and twenty-three (123) (82%) of the lizards. In Oba-Ama, forty-five (45) (76.3%) out of 59 and in Ogoloma-Ama, seventy-eight (78) (84.8%) out of 92 were infected with helminths. By abundance, in both locations, the males were more infected than their female counterparts with a prevalence of 51(93%) and 72(75%) (P<0.05), respectively. This study has revealed the helminth parasites infecting the agamid lizard of Rivers State, Nigeria. It has also shown some unidentified species of Mesocoelium and Oochoristica sp. Additionally the trapping system used was also found to be effective and efficient.

Relationship between External Morphology and Gonads in Rainbow Lizard (Agama agama) in Obafemi Awolowo University, Ile-Ife, Nigeria

Background of the Study: The morphology of any reptile may be affected by different environmental factors such as climate change and habitat related features such as availability of food and other resources.
 Objective: This study aimed at determining the morphology and sexual variation of Rainbow male and female lizards (Agama.agama) in Obafemi Awolowo University. 
 Study Design: Three locations in the University were selected (Student Hostels, Academic Area and Staff Quarters) and rainbow lizards were sampled from June to December 2019. 
 Results: A total of 93 lizards were sampled, body parameters were measured, and the gonads were weighed after dissection. There was a positive correlation (0.98 & 0.78) between the body weight and gonad weight of the male and female lizards in all the three locations. Also, the specimen from the academic area of the University had the least body and gonad weight, while the samples caught in the staff quarters had the highest body and gonad weight. The Principal Component Analysis (PCA) showed a relationship in the body and gonad weight with few differences from samples captured in the academic area. 
 Conclusion: In summary, external morphology of the rainbow lizards from all the three locations were similar with little difference in body weight. There was a positive relationship between external morphology and gonads of rainbow lizards.

Geographic variation in West African Agama picticauda: insights from genetics, morphology and ecology

ABSTRACTWest Africa is a region characterised by high species diversity and endemism, making it an ideal region to study the evolution of genetic and phenotypic differentiation. Species in this region often vary in morphology and genetics; however, the specific drivers of these differences have not been clearly identified. Focusing on populations in Ghana, we tested for correlations between geography, genetic diversity, morphology and ecology in the West African rainbow lizard (Agama picticauda). Genetic data were collected from 102 specimens using double-digest restriction site-associated DNA sequencing (ddRADseq) and the final data matrix included 5 976 loci and 20 624 single nucleotide polymorphisms (SNPs). Morphological data were collected from 42 specimens and included 6 meristic and 4 mensural characters. Ecological data were obtained from the WorldClim database to a resolution of 30 arcseconds. Population structure analyses supported up to five distinct populations of A. picticauda in Ghana. Discriminant function analyses were used to classify samples using the morphological data and ecological data. Ecology showed the strongest correlation with population genetic structure, whereas morphological data were only able to weakly differentiate three populations. We discuss the factors that might be responsible for correlations between phenotypes and genotypes in the context of A. picticauda natural history.

Confirmation of introduced Agama picticauda in Florida based on molecular analyses

As of 2010, Florida had the largest number of introduced and established non-indigenous herpetofaunal species in the world. With the advent of molecular methodologies, researchers now are able to test hypotheses regarding introduction pathways, species identity, and native range origins. African Agamas, Agama Daudin 1802, found in Florida are hypothesized to be the African Rainbow Lizard, A. agama africana Hallowell 1844, based on color patterns and hypothesized native range origins (i.e., Benin, Ghana, and Togo) of imported specimens for the pet trade. However, recent systematic studies within the native range of the Agama complex have resulted in multiple taxonomic revisions, which calls into question the species identity of introduced populations in Florida. The purpose of this study is to determine the species identity of African agamas within Florida, as well as the native range origins of Florida populations. We conducted a comparative maximum likelihood analysis between individuals from Florida and individuals from the native range. Based on our results we determined that the species found in Florida is Agama picticauda from western Africa.

Effects of rainfall and geography on the comparative diets of eight rainbow lizard populations across Togo, Benin and Nigeria (West Africa)

The diet composition of rainbow lizards (Agama agama complex) populations was studied by feces analysis at eight distant places across a mega-transect in the Gulf of Guinea (West Africa), covering three countries: Togo, Benin and Nigeria. The effects of geography (= linear distance between study sites) and local conditions (using the mean annual rainfall as a proxy of the site-specific conditions) on dietary similarity of rainbow lizards were tested. Rainbow lizards were mainly insectivorous at all sites. Multivariate analyses identified four main groups of localities in terms of diet diversity indexes, with populations inhabiting forest towns tending to have less prey taxa richness than conspecifics from more arid areas, which instead had higher dietary evenness. Food niche overlap between populations was high among populations (range 0.631-0.940, ), and decreased with increases in the difference of mean annual rainfall between sites. There was no effect of the geographic distance on the similarity in diet composition between populations. A UPGMA dendrogram revealed a geographic trend in terms of presence/absence of the various prey types in the diets, with all the Nigerian study sites forming one cluster, whereas Lomé and Cotonou, two cities situated within the Dahomey Gap, being grouped apart. Overall, rainfall of the various sites seems to be more important than geographic distance for determining the taxonomic diet composition similarity of these lizards.

Stomach flushing affects survival/emigration in wild lizards: a study case with rainbow lizards (Agama agama) in Nigeria

AbstractStomach flushing is one of the proposed techniques to study lizard diets. Apparently, it is ranged, together with direct observation and faecal analysis, as a non-harmful method for dietary studies. Some works explored the usefullness of stomach flushing, but we lack information about its effect on lizard's survival probabilities. In this paper we studied the effect of stomach flushing in an urban population of the rainbow lizard (Agama agama) from Calabar (Nigeria). During a period of five months of 2010, 147 lizards were noosed, sexed and individually marked. One group of lizards was stomach flushed only once, whereas the rest of lizards were not flushed. The flushed sample of lizards showed a lower survival than non-flushed lizards of all sex and age classes. In this study, the pictured diet from stomach flushing was very similar to results obtained with a faecal analysis of the same lizard population. Thus, both methods seem to be reliable to study the diet of the rainbow lizard. However, our results indicate that stomach flushing increases the probability of mortality (or at least emigration rates) in all age and sex classes, precluding its extensive use as a method to study lizard's diets.

Helminth parasites of the African lizard Agama agama (Squamata: Agamidae), in Lagos, Nigeria

Agama agama, the agamid rainbow lizard, has been reported to serve as transport and reservoir host to several protozoan and helminth parasites. We randomly sampled 310 specimens between May and July, 2005, at Oyingbo, Lagos, Nigeria (6 degrees 34'60" N-3 degrees 19'59" E and 6 degrees 34'60" N-3 degrees 19'59" E).They harboured four species of nematodes: Strongyluris brevicaudata, Parapharyngodon awokoyai, Capillaria sp. and Oxyuris sp.; one of Cestoda, Oochoristica agamae; one of Trematoda, Mesocoelium monas; and one of Pentastomida, Raillietiella sp. Strongyluris brevicaudata had the highest prevalence of infection (82.3%), followed by P. awokoyai (74.5%), Raillietiella (10.3%), Capillaria sp. (8.4%) and O. agamae (7.4%). M. monas and Oxyuris sp. had low prevalences: 1.61% each. Raillietiella sp. and Capillaria sp. can cause localized inflammation and intestinal infections in humans. The prevalence of infection was higher in larger adult lizards. Prevalence in males was 97.6% (94.1% in females). In four of the helminth species, intensity of infection was higher in male lizards. Parasite intensity was highest in the rectum, followed by the intestine (p<0.05). Infection intensity was, to a large extent, dependent on the type of parasite, and age of lizard. During May, P. awokoyai had its highest mean intensities and prevalence. The prevalence and mean intensity of helminthes varied with the month of collection (both p<0.05). For the three months studied, prevalence and mean intensity of S. brevicaudata were highest in June (July for the other species).

Notes on the ecology of a suburban population of Rainbow lizards in coastal Kenya

Aspects of the ecology of a suburban population of rainbow lizards, Agama agama Linnaeus 1758, have been studied in Malindi, a coastal locality of SE Kenya. Four different family groups were monitored on a wall transect 120 m long. Each group constituted a dominant male (i.e. a brightly coloured and aggressive individual) and three to four adult females, but in one of the studied groups a subordinate male was also seen. Both sexes were active in the morning, and peak activity fell between 10.00 and 11.30 hours. Dominant males used elevated perches significantly more often than subordinate males and females. The diet consisted of terrestrial arthropods, and most of the prey eaten were beetles (6–8 mm long). The foraging strategy used by rainbow lizards was to eat small insects at very short time intervals. The lizards used sit‐and‐wait foraging, remaining motionless until the prey was &lt;5 cm away. The rainbow lizards studied did not feed upon plant material.

Interspecific interactions tested: two species of malarial parasite in a West African lizard.

Plasmodium giganteum and P. agamae, parasites of the rainbow lizard, Agama agama, in West Africa were studied to determine the nature of any interspecific interactions between the two malaria species. The plasmodia are distributed in A. agama throughout the mesic zone of Africa; P. agamae is sometimes found as a solitary malaria species in populations of the lizard, but P. gigateum has not been found alone. In 3170 lizards from Sierra Leone the prevalence of lizard malaria at 22 sites varied considerably (8-90% of lizards were infected), but the ratio of the two species was similar among sites (52-91% P. agamae). Larger lizards were more often infected. Mixed infections occurred 2-5 times more often than expected by chance. Parasite density within individual hosts, or parasitemia, was similar for each species when alone or in mixed infection. Natural infections followed in laboratory lizards stayed at constant levels for as long as 211 days. The two species use different classes of host cells (P. giganteum in immature cells and P. agamae in mature erythrocytes) and may have different periods of peak transmission. Analysis of the data does not support a neutral relationship between P. giganteum and P. agamae, nor ongoing competition for resources or heterologous immunity. The data best support facilitation in which P. agamae alters the host in a way that allows more successful establishment of P. giganteum.

Characteristic features of the sonicated DNA of Agama agama agama L. (Reptilia, Agamidae) on hydroxyapatite columns, using mouse DNA as a reference

Hydroxyapatite column chromatography has been used to study some properties of the extensively sheared DNA of the Rainbow lizard, Agama agama agama. Reassociation studies show that the genome has a Cot1/2 of 370. Approximately 15% of the genome is highly repetitive in nature. This repetitive fraction is resolved into thermally stable and less stable fractions. The stable fraction has a base composition of 47% GC, higher than the 40.2% GC for the native DNA. This stable fraction is believed to be of recent origin. Chromatography of the total DNA of the lizard with linear gradients of phosphate buffer containing 1 M urea resolves it into two components which were shown by thermal fractionation, also in the presence of 1 M urea, to vary in base composition. This behaviour may be characteristic of reptilian genomes and may be used as a basis for studying the structural organisation of the reptilian genome.

A comparative study of rhodanese activity in some lizard species

1. Rhodanese activity has been determined in some organs of three species of lizards, namely: rainbow lizard, wall gecko and skink. 2. While the activity was significantly higher in the livers of all the species compared to that in the kidney, small intestine and the brain, there were significant differences in the enzyme in the livers of the different species. The activity was highest in the liver of the rainbow lizard followed by that of wall gecko and then skink. 3. The order of activity of the enzyme in the organs of the rainbow lizard was liver > kidney > small intestine > brain. 4. The high level of rhodanese in lizard tissues suggests that the enzyme may be involved in roles other than cyanide detoxification.

Virulence of lizard malaria: the evolutionary ecology of an ancient parasite—host association

The negative consequences of parasitic infection (virulence) were examined for two lizard malaria parasite-host associations: Plasmodium agamae and P. giganteum, parasites of the rainbow lizard, Agama agama, in Sierra Leone, West Africa; and P. mexicanum in the western fence lizard, Sceloporus occidentalis, in northern California. These malaria species vary greatly in their reproductive characteristics: P. agamae produces only 8 merozoites per schizont, P. giganteum yields over 100, and P. mexicanum an intermediate number. All three parasites appear to have had an ancient association with their host. In fence lizards, infection with malaria is associated with increased numbers of immature erythrocytes, decreased haemoglobin levels, decreased maximal oxygen consumption, and decreased running stamina. Not affected were numbers of erythrocytes, resting metabolic rate, and sprint running speed which is supported by anaerobic means in lizards. Infected male fence lizards had smaller testes, stored less fat in preparation for winter dormancy, were more often socially submissive and, unexpectedly, were more extravagantly coloured on the ventral surface (a sexually dimorphic trait) than non-infected males. Females also stored less fat and produced smaller clutches of eggs, a directly observed reduction in fitness. Infected fence lizards do not develop behavioural fevers. P. mexicanum appears to have broad thermal buffering abilities and thermal tolerance; the parasite's population growth was unaffected by experimental alterations in the lizard's body temperature. The data are less complete for A. agama, but infected lizards suffered similar haematological and physiological effects. Infected animals may be socially submissive because they appear to gather less insect prey, possibly a result of being forced into inferior territories. Infection does not reduce clutch size in rainbow lizards, but may lengthen the time between clutches. These results are compared with predictions emerging from several models of the evolution of parasite virulence. The lack of behavioural fevers in fence lizards may represent a physiological constraint by the lizards in evolving a thermal tolerance large enough to allow elimination of the parasite via fever. Such constraints may be important in determining the outcome of parasite-host coevolution. Some theory predicts low virulence in old parasite-host systems and higher virulence in parasites with greater reproductive output. However, in conflict with this argument, all three malarial species exhibited similar high costs to their hosts.

Demonstration of prostaglandin activity in longs of the rainbow lizard (Agama agama) by bioassay

Extracts and perfusate effluents of lungs of the rainbow lizard (Agama agama) were assayed for prostaglandin-like activity. Results of differential bioassay and thin-layer chromatography suggested that the prostanoid was predominantly PGE2-like. The mean PGE2-like content of 10 lizard lung extracts was 2.9 micrograms g-1 wet weight compared with 146 ng g-1 in rat lungs. Mechanical pressure applied to the lung during perfusion through the pulmonary vasculature provoked the release of large quantities of PGE2-like material. This release was blocked by fatty acid cyclooxygenase inhibitors. Compared with guinea-pig and rat lungs, lizard lungs exhibited a markedly low capacity for inactivating PGE2. In view of an apparently high prostaglandin-forming and a low inactivating capacity, we speculate that under certain circumstances, lizard lungs may release vasoactive substances into the circulation.

A comparative study of superoxide dismutase in various animal species

1. 1. Superoxide dismutase activity has been determined in liver homogenates of five species. There were no significant differences in the activities of the enzyme in the rat, rainbow lizard, will gecko and chicken. The activity was significantly lower in the fish. 2. 2. The order of activity of the enzyme in the organs/tissues of the rat was liver > kidney > heart > skeletal muscle > brain > lung > spleen > spinal cord > retina > pancrease > lens > small intestine. 3. 3. Inhibition studies with cyanide showed that the enzyme in the liver of the various animal species was inhibited by cyanide. 4. 4. The developmental pattern for the enzyme showed no significant changes in the liver of the rat from birth and up to 7 weeks after. However, the activity increased at about 8 weeks and remained constant to adult life.

The sex ratio of Plasmodium gametocytes.

Sex ratio theory usually predicts an equilibrium sex ratio and equal proportions of males and females in a population, including the progenitors of the reproductive cells of protozoans. This proposal was tested with three species of malarial parasites of lizards, Plasmodium mexicanum of the western fence lizard, and P. agamae and P. giganteum of the African rainbow lizard, using single samples from naturally infected lizards, repeated samples from free-ranging lizards (P. mexicanum only), and repeated samples from laboratory maintained animals. Macrogametocytes were usually more abundant than microgametocytes, and were slightly larger, revealing a typically greater investment of resources by the progenitors of female reproductive cells. However, the proportion of microgametocytes varied among the three species and among infections within each species of Plasmodium. The sex ratio of gametocytes often remained constant within infections followed over time even if the absolute number of gametocytes was changing. However, the equilibrium sex ratio of gametocytes varied among those infections that had an unchanging microgametocyte proportion. Thus, although an equilibrium sex ratio apparently occurs for most infections, there appears to be no characteristic proportion of microgametocytes for any of the species. Potential explanations for this conflict with theory are presented.

Responses of the isolated rectum of the rainbow lizard (Agama agama) to sympathomimetics

The relaxant effects of isoprenaline, noradrenaline, and adrenaline on the isolated rectum of the rainbow lizard (Agama agama) were studied. Responses were measured as a reduction of carbachol-induced contractions for each sympathomimetic agent. Isoprenaline, adrenaline, noradrenaline produced a dose-dependent relaxation of this preparation and the order of potency was as given. The pD2 value of 8.15 +/- 1.88 obtained for isoprenaline was significantly different (p less than 0.05) from those for adrenaline (5.80 +/- 0.90) and noradrenaline (5.25 +/- 1.18). H35/25, propranolol, and practolol competitively antagonized the relaxant effects of isoprenaline on the isolated lizard rectum. The pA2 values for these beta-adrenoceptor antagonists did not differ significantly (at p less than 0.05). alpha-Adrenoceptor antagonists, phentolamine and phenoxybenzamine, failed to alter the relaxant responses of these sympathometics to any appreciable extent. These results are interpreted to suggest that the relaxant effect produced by these sympathomimetics are mediated predominantly by beta-adrenoceptors that are not significantly differentiated into subtypes. alpha-Adrenoceptors in this preparation contribute minimally to the observed inhibitory response following sympathomimetic stimulation.