Field observations and feeding experiments on the responses of rufous-tailed jacamars (Galbula ruficauda) to free-flying butterflies in a tropical rainforest

Abstract

Wild rufous-tailed jacamars (Calbula rujcaudu) were shown to prey frequently, but selectively, upon butterflies in a Costa Rican rainforest. Two individually caged birds (a male and a female) were further tested with over 1000 butterflies of I14 morphs. Both wild jacamars and the two captive individuals were able to capture and handle all kinds and sizes of local butterflies. These butterflies (and other winged insects) were recognized by the jacamars as prey only through their movement. l h e captive birds discriminated between an unacceptable group of butterflies, which generally fly slowly or regularly, are warningly coloured and mimetic, with transparent, or white, orange, red, and/or black coloration, and an acceptable group that generally fly fast or erratically, are cryptic (on one or both sides), and have yellow, orange, green, blue, and/or brown coloration. These different morphological and behavioural characteristics of butterflies presumably helped the jacamars to assess their palatability.Most individuals of unacceptable butterflies (e.g. Baffus and Purides (Papilionidae), some Pieridae, Diaethria and Callicore (Nymphalinae), Heliconiinae, Acraeinae, Ithomiidae, and Danaidae) were sight-rejected by the male jacamar (Jacamar 2), and many of the same were also sight-rejected by the female (Jacamar 1). In cases when the above butterflies were attacked, they were quickly released and usually unharmed. The captive female bird, after long periods without food, consumed many pierid and heliconiine butterflies that were consistently rejected by the male for their distasteful and dangerous qualities. In contrast, palatable butterflies (e.g. Papilio, Charaxinae, most Nymphalinae, Morpho, Brassolinae, and Satyrinae) were usually quickly attacked and consumed. The captive jacamars were able to discriminate between the very similar colour patterns of some Batesian mimics and their models, and could memorize the palatability of a large variety of butterflies. The discriminatory abilities of specialized insectivorous birds such as jacamars are likely to play a major role in the evolution of neotropical butterfly mimicry.

Size-dependent colouration in larvae of Orgyia antiqua (Lepidoptera: Lymantriidae): A trade-off between warning effect and detectability?

“…In particular, aposematic larvae are not safe because bird species differ in their ability to discriminate between aposematic and nonaposematic prey (Exnerová et al, 2003), also the threshold signal strength that creates the aversion appears to vary (Exnerová et al, 2006). The birds' willingness to consume aposematic prey also strongly depends on their hunger level as the results of the current and some other studies show (Chai, 1986;Sandre & Mappes, in prep.). It can also depend on their ability to overcome prey defences, both within (Bowers & Farley, 1990) and between species (Exnerová et al, 2003), the presence of alternative prey (Hetz & Slobodchikoff, 1988;Lindström et al, 2001Lindström et al, , 2004, earlier experience (Endler, 1988;Lindström et al, 1999aLindström et al, , 2001Exnerová et al, 2007), within-species genetic biases (Marples & Brakefield, 1995), and more.…”

Discrimination of flying mimetic, passion–vine butterfliesHeliconius

“…Aerial predators that choose to attack or ignore butter£ies in £ight, such as rufous-tailed jacamars (Chai 1986(Chai , 1990, are the most likely selective agents for convergence in £ight behaviour.…”

Paradox lost: variable colour-pattern geometry is associated with differences in movement in aposematic frogs

“…However, these studies do not consider aposematic species, which have different dynamics than cryptic species [2]. At the species level, birds can discriminate palatable from unpalatable butterflies on the basis of their flight [16]. Palatable butterflies fly fast or erratically and have inconspicuous coloration, whereas unpalatable species fly slowly or regularly and are conspicuously, warningly coloured [16].…”

“…At the species level, birds can discriminate palatable from unpalatable butterflies on the basis of their flight [16]. Palatable butterflies fly fast or erratically and have inconspicuous coloration, whereas unpalatable species fly slowly or regularly and are conspicuously, warningly coloured [16]. That example, however, does not address variable aposematic coloration within a species.…”