Color change and color-dependent behavior in response to predation risk in the salamander sister species Ambystoma barbouri and Ambystoma texanum

Abstract

Although many organisms show multiple types of trait responses to predation risk (e.g., shifts in behavior, morphology, color, chemistry or life history), relatively few studies have examined how prey integrate these multiple responses. We studied the joint expression of color and behavioral responses to predation risk in two sister species of salamander larvae that live in habitats with different selection pressures. We examined responses to predation risk in three situations that differed in availability of refuge and substrate color heterogeneity, and thus availability of behavioral options for reducing risk. Relative to Ambystoma texanum, A. barbouri larvae were darker in color and showed a greater range of color change. With no variation in background color or refuge available, both species exhibited color change to better match the available background. The degree of color change showed by both species, however, did not depend on predation risk. Given the option to choose between light and dark substrates, A. texanum exhibited behavioral background matching (i.e., they preferred substrates that matched their own body color), while A. barbouri's substrate preferences did not depend on their initial body color. Instead, A. barbouri responded to risk by showing a strong preference for dark substrates, followed by a change to a darker body color. With refuge available, A. texanum's refuge use was color-dependent; larvae that were well camouflaged spent less time in refuge. In contrast, A. barbouri showed strong refuge use in response to risk, regardless of their body color. Overall, these results reflect how conflicting selection pressures (predation risk, habitat ephemerality, risk of UV damage) and species differences in mean color and ability to change color can govern the interplay of complementary and compensatory behavioral and color responses to predation risk.

The variable colours of the fiddler crabUca vomerisand their relation to background and predation

“…Salamander tadpoles, for instance, respond to the presence of fish chemical cues by changing colour to better match the available background (Garcia and Sih, 2003). In cephalopods, which can change their body colour patterns on the time scale of seconds, the high variability may serve functions in both camouflage and communication (Hanlon et al, 1999).…”

Costs of colour change in fish: food intake and behavioural decisions

“…Prey animals often have a repertoire of potential responses to increased predation risk, ranging from immediate behavioural responses to plastic morphological change to shifts in life history strategies (Garcia and Sih, 2003). We show here that colour change to match the visual background is complemented by behavioural strategies that minimise the need to pay the cost associated with colour change, but which may also represent an opportunity cost to the individual.…”

“…Strand et al, 2007). In guppies, the highest predation risk generally occurs at maximum light levels (Endler, 1987), and in salamanders (Ambystoma barbouri and A. texanum), the presence of olfactory cues from predatory fish resulted in a preference for dark substrates over light ones (Garcia and Sih, 2003). There is also evidence that living in light-coloured habitats may have other costly implications for fish: growth and survival in juvenile yellow seahorses (Hippocampus kuda), for example, were significantly reduced in light habitats compared with dark ones (Pawar et al, 2011).…”

“…Many animals are known to select habitats that best match their colouration (known as 'behavioural background matching') in order to increase crypsis and reduce predation (Garcia and Sih, 2003;Ruxton et al, 2004). Both black-and white-adapted fish avoided habitats of the opposite colour, where they would be most conspicuous, preferring instead those where they were more cryptic.…”

“…Behavioural background matching (Garcia and Sih, 2003) is widespread in the animal kingdom, where prey animals select microhabitats that enhance their crypsis to avoid predation. Brown and green morphs of the Pacific tree frog Hyla regilla preferentially select brown and green substrates, respectively (Wente and Phillips, 2003;Wente and Phillips, 2005), and pale and dark morphs of the cichild fish Telmatochromis temporalis defend territories in open (light) or shaded habitats, according to their body colour (Mboko and Kohda, 1995).…”