Stimulus control of predatory behavior by the Iberian wall lizard (Podarcis hispanica, Sauria, Lacertidae): Effects of familiarity with prey.

Abstract

The authors examine the relative roles of vision and chemoreception and the influence of previous experience with prey on the predatory behavior of Iberian wall lizards (Podarcis hispanica). Experiment 1 compared the responses to visual, chemical, and a combination of visual and chemical cues of a familiar prey by 2 groups of lizards that had been kept in captivity for either 3 months or 21 days. Experiment 2 assessed the responses of lizards kept in the laboratory for more than 3 months to a novel prey species. The results reveal that feeding on a prey species affects the lizards' responses to chemical stimuli from that prey. The response to chemical cues of a novel prey requires a 1st-feeding experience with that prey. Lizards that have been fed the same prey species for several months cease responding to the chemical stimuli of that particular prey.

The peculiar case of an insectivorous iguanid lizard that detects chemical cues from prey

“…Chemical exploration (number of tongue flicks) was significantly higher in the areas with chemical cues from mealworms, and this behavior was modulated by experience. Lizards that were naïve to the prey explored more in the area with chemical cues, similar to what was found in the active forager Podarcis hispanica (Desfilis et al, 2003). Because experience in L. lemniscatus only affected the number of tongue flicks, we may rule out the hypothesis that reduced chemical exploration in experienced lizards was a consequence of reduced motivation to search for prey.…”

“…Thus, for L. zapallarensis, swabs could be an inappropriate experimental protocol (see Cooper et al, 2000;Clark, 2004). In addition, because experience with the prey can reduce the lingual chemical exploration to their chemical cues (Desfilis et al, 2003;this study), L. zapallarensis may not have responded due to familiarity with the prey presented to them (Burghardt, 1992;1993 and references herein). Although there was no information about the previous diet at which individuals of L. zapallarensis were maintained (De Perno and Cooper, 1993), crickets is the most likely candidate, and thus, a lack of chemical discrimination is expected.…”

“…To ensure adequate responses to mealworms stimuli, lizards did not receive food five days before the experiments (e.g., Desfilis et al, 2003). Individuals captured in March were housed for five days without food.…”

“…This species is an insectivorous ambush forager, which spends most of its active time stationary on rocks or on ground (Fuentes, 1976;Núñez et al, 1989;Labra and Leonard, 1999). Because I tested chemical detection of mealworm larvae (Tenebrio molitor), a prey that does not normally occur in the L. lemniscatus diet, I also investigated the effect of experience with the prey on the ability to detect it, since experience can modify motivation to search for prey (Desfilis et al, 2003). Enclosures had a small window in the front (10 × 5 cm) covered with a plastic mesh, allowing more light.…”

Chemical stimuli mediate species recognition in Podarcis wall lizards

“…However, these authors did not test the ability of P. carbonelli males to discriminate between chemical cues of their own and those of the other species. Moreover, the use of cotton swabs in chemical discrimination studies is controversial, since the cotton swab adds an unwanted visual stimulus that may complicate interpretation of the results (Cooper, 1998;Desfilis et al, 2003). Our experimental design using labelled substrates, on the other hand, provides a more naturalistic approach and may thus have more ethological validity (Greenberg, 1994).…”