Acquired preferences for a novel food odor do not become stronger or stable after multiple generations of odor feeding in Bicyclus anynana butterfly larvae

Abstract

Many herbivorous insects have specific host–plant preferences, and it is unclear how these preferences evolved. Previously, we found that Bicyclus anynana larvae can learn to prefer novel food odors from eating leaves with those odors and transmit those learned preferences to the next generation. It is uncertain whether such acquired odor preferences can increase across generations of repeated odor feeding and be maintained even in the absence of odor. In this study, we fed larvae with novel banana odor‐coated leaves (odor‐fed larvae) for five consecutive generations, without selection on behavioral choices, and measured how larval innate preferences changed over time. Then, we removed the odor stimulus from a larval subgroup, while the other group continued to be odor‐fed. Our results show that larvae learned to prefer the novel odor within a generation of odor feeding and transmitted the learned preference to the next generation, as previously found. Odor‐fed larvae preferred odor significantly more compared to control larvae across five generations of repeated odor or control feeding. However, this led neither to increased odor preference, nor its stabilization. This suggests that when butterfly larvae feed on a new host, a preference for that novel food plant may develop and be transmitted to the next generation, but this preference lasts for a single generation and disappears once the odor stimulus is removed.

Pupal and Adult Experience Affect Adult Response to Food Odour Components in the Flower-Visiting Butterfly Tirumala limniace

“…The phenomenon of memory persisting through metamorphosis, i.e., preimaginal memory persists into the adult form, has been reported in several insects, such as flies [30,31], parasitic wasps [32], moths [33], and ants [34]. Gowri and Monteiro [35] found that B. anynana larvae learned to prefer the novel odour within a generation of odour feeding and transmitted the learned preference to the next generation. We found the newly emerged T. limniace adults could maintain the memory experienced during the pupal stage.…”

Haemolymph transfusions transfer heritable learned novel odour preferences to naive larvae of Bicyclus anynana butterflies

“…Bicyclus anynana is a subtropical model nymphalid butterfly that can learn preferences for novel visual cues [16,17] and transmit learned chemical cues to their offspring [8,18]. In previous studies, we showed that larvae that fed on an innate aversive odour, acquired a novel preference for that odour and produced naive offspring that inherited that odour preference [8,19].…”