Biomedical subjects

Luisa Amo

Publications and source records attributed to Luisa Amo.

5 recordsLinked to original sources

PubMed2007

Pregnant female lizards Iberolacerta cyreni adjust refuge use to decrease thermal costs for their body condition and cell-mediated immune response.

Lizards often respond to increased predation risk by increasing refuge use, but this strategy may entail a loss of thermoregulatory opportunities, which may lead to a loss of body condition. This may be especially important for pregnant oviparous female lizards, because they need to maintain optimal body temperatures as long as possible to maximize developmental embryos rate until laying. However, little is known about how increased time spent at low temperatures in refuges affects body condition and health state of pregnant female lizards. Furthermore, it is not clear how initial body condition affects refuge use. Female Iberian rock lizards forced to increase time spent at low temperatures showed lower body condition and tended to show lower cell-mediated immune responses than control females. Therefore, the loss of thermoregulatory opportunities seems to be an important cost for pregnant females. Nevertheless, thereafter, when we simulated two repeated predatory attacks, females modified refuge use in relation to their body condition, with females with worse condition decreasing time hidden after attacks. In conclusion, female lizards seemed able to compensate increased predation risk with flexible antipredatory strategies, thus minimizing costs for body condition and health state.

Analysis of Variance↗

PubMed2006

Refuge use: a conflict between avoiding predation and losing mass in lizards.

Prey often respond to predation risk by increasing refuge use, but this strategy may entail a loss of body condition. Factors responsible for this loss of body condition remain unclear. Also how prey deal with refuge use to cope with predation risk without incurring costs of body condition, and how initial body condition affects refuge use remain barely known. We analyzed in the field whether adult Iberolacerta cyreni lizards modify their escape strategies and refuge use in areas with different levels of habitat deterioration and ecotourism pressure, which represent different levels of predation risk, and the consequences of changes in antipredator behavior to body condition. Lizards inhabiting deteriorated areas, where risk is higher, remained closer to refuges, but decreased time spent hidden in refuges after attacks, probably to maintain similar body condition than lizards inhabiting natural areas. We performed two laboratory experiments to isolate potential costs of refuge use that might affect the body condition of male lizards: a) a decrease of the efficiency of digestion due to low temperatures inside refuges and/or b) a reduction in food intake. Results suggest that refuge use is costly in terms of body condition due to reduced food intake, but the loss of efficiency of digestion seems unimportant. Lizards modified refuge use in relation to their body condition, with lizards with worse condition decreasing time hidden after predatory attacks. We concluded that lizards compensated for increased predation risk with flexible antipredatory strategies, coping with risk without incurring costs for body condition.

Adaptation, Physiological↗

PubMed2006

Reliable signaling by chemical cues of male traits and health state in male lizards, Lacerta monticola.

In spite of the importance of chemoreception in social organization and sexual selection of lizards, there is a lack of general knowledge on how the characteristics of chemical signals mediate these behaviors. Moreover, it is unknown which are the mechanisms that might confer honesty to the information provided by chemical signals. We analyzed here whether characteristics of the lipophilic fraction of femoral gland secretions of Lacerta monticola male lizards can be related to the morphology, physical condition, and health state of the sender. Our results indicated that some male traits, such as body size, number of blue spots, and number of femoral pores and their level of fluctuating asymmetry, were related to variability in the relative proportions of some lipophilic chemical compounds found in secretions. Thus, conspecifics could obtain reliable information on the producer of a scent mark based on chemicals alone, and this might be the basis of female choice observed in this lizard. Moreover, only males with a greater T-cell immune response had higher proportions of two steroids (ergosterol and dehydrocholesterol) in their femoral secretions, which might suggest that the signal is honest and costly to produce. We suggest that only high-quality males could divert these compounds from metabolism to secretions in order to produce an exaggerated and honest "chemical ornament."

Animals↗

PubMed2004

Thermal dependence of chemical assessment of predation risk affects the ability of wall lizards, Podarcis muralis, to avoid unsafe refuges.

Prey often respond to predators by increasing refuge use, but some refuges may expose prey to other types of predators. Because predators are not always visible inside refuges, their chemical stimuli may provide early warning of their presence. However, in ectotherms, chemosensory detection of predators may be thermally dependent. Lizards often hide in cold refuges, where their body temperature (Tb) may decrease, and this might affect their ability to detect chemicals of saurophagous snakes that ambush inside refuges. We examined the effects of Tb of wall lizards, Podarcis muralis, on their ability to detect chemicals of smooth snakes, Coronella austriaca. Differential tongue flick (TF) rates and behavioral patterns of lizards in response to scent of smooth snakes showed that lizards with optimal Tb discriminated and avoided the snake's scent, whereas lizards with suboptimal Tb did not. We also examined the importance of this effect on movement patterns and refuge use by lizards in terraria with safe (odorless) or unsafe refuges (snake-scented). While results of this experiment were variable, there was evidence of snake avoidance in that lizards at optimal Tb spent less time in snake-scented refuges relative to odorless refuges. Therefore, this study provides evidence that chemosensory discrimination of snake chemicals is thermally dependent, and, thus, suboptimal Tb impedes a lizard's ability to avoid snake-scented refuges.

Analysis of Variance↗

PubMed2004

Double gametocyte infections in apicomplexan parasites of birds and reptiles.

The simultaneous occurrence of male and female gametocytes inside a single host blood cell has been suggested to enhance apicomplexan transmission ["double gametocyte infection (DGI) hypothesis"]. We did a bibliographic search and a direct screen of blood smears from wild birds and reptiles to answer, for the first time, how common are these infections in the wild. Taking these two approaches together, we report here cases of DGIs in Plasmodium, Haemoproteus, Leucocytozoon and Hepatozoon, and cases of male-female DGIs in Haemoproteus of birds and reptiles and in Leucocytozoon of birds. Thus, we suggest that DGIs and male female DGIs are more widespread than previously thought, opening a new research avenue on apicomplexan transmission.

Animals↗