Can embryonic skipper frogs (Euphlyctis cyanophlyctis) learn to recognise kairomones in the absence of a nervous system?

Abstract

In this study, we used larval Euphlyctis cyanophlyctis to determine the predator recognition mechanism. We conducted a series of experiments to determine if larval E. cyanophlyctis have the innate ability to recognise predatory odour (kairomones) as a threat or if they learn to do so during ontogeny. In the case of learning, we wanted to determine the developmental window during which learning is accomplished. Further, we tested the antipredator response of predator- naive as well as predator-experienced tadpoles to chemical cues of different origins in order to assess if they exhibit differential responses. Our results clearly indicate that predator-naı¨ve tadpoles of E. cyanophlyctis do not reduce their activity against predatory cues of dragonfly nymphs, suggesting that they lack the innate ability to recognise kairomones. However, they could learn to do so when trained to perceive kairomones simultaneously along with alarm cues. Surprisingly, larval E. cyanophlyctis could learn to recognise kairomones through association during embryonic stages even before the development of a nervous system. Although larval E. cyanophlyctis lack the innate ability to recognise kairomones, they were able to recognise conspecific alarm cues on the first encounter, indicating that they have the innate ability to recognise alarm cues as a potential threat.

Does atrazine induce changes in predator recognition, growth, morphology, and metamorphic traits of larval skipper frogs (Euphlyctis cyanophlyctis)?

“…An established behavioral assay was used to assess the effect of ATZ on the antipredator response (Supekar & Gramapurohit, 2017, 2022). The behavioral assay was carried out ~27 days after the initiation of the experiment.…”

“…The behavioral assay was carried out ~27 days after the initiation of the experiment. Conspecific alarm cues were prepared following the protocol established earlier (Supekar & Gramapurohit, 2017). Briefly, five tadpoles (0.41 g) of stages 27−28 were frozen to deep hypothermia (at 0°C for 10−15 min) and quickly crushed with a mortar pestle.…”

“…The transmission of information between organisms using chemical cues is an integral component of prey−predator interaction (Ferrari et al, 2010). Chemical cues are not only critical for the detection of potential predators but also crucial in providing information about the intensity of risk and its temporal variation (Lönnstedt et al, 2012; Mogali et al, 2011; Peacor et al, 2006; Supekar & Gramapurohit, 2017, 2018, 2020a, 2020b). In aquatic ecosystems, prey animals generally rely on chemical cues for recognizing their potential predators as they can diffuse rapidly, efficient in detecting predators even at night and in murky environments (Dodson et al, 1994; Ferrari et al, 2010; Mogali et al, 2012, 2015; Saidapur et al, 2009; Scherer & Smee, 2016).…”

“…Larval E. cyanophlyctis lack an innate ability to recognize kairomones of the dragonfly nymphs as a threat. However, they have the innate ability to recognize conspecific alarm cues and use alarm cues to label kairomones of dragonfly nymphs as a threat (Supekar & Gramapurohit, 2017, 2018). Hence, we wanted to know if ATZ alters the innate ability to recognize alarm cues in addition to its effects on growth, morphology, and metamorphic traits of larval E. cyanophlyctis .…”

Chemically-induced plasticity in early life history ofPalaemon argentinus: are chemical alarm cues conserved within palaemonid shrimps?

“…there is a critical embryonic period conditioning the morphological responses of hatchlings (Mandrillon and Saglio, 2008). Nevertheless, embryos of the skipper frog Euphlyctis cyanophlyctis seem to recognise infochemicals, indicative of predation risk even before neurulation (Supekar and Gramapurohit, 2017). For most invertebrate taxa, however, information on whether embryonic responses to chemical predation cues occur at any point in development or if there are windows of sensitivity/responsiveness is still scarce.…”