Coevolution of Plants and Herbivores: Passion Flower Butterflies

Abstract

Plant specific insect herbivores are remarkable not only in their ability to locate and identify the appropriate host, but also in that they very often show a "botanical instinct" (Brues, 1920(Brues, , 1924: closely related insects choose closely related plants.For both insects and plants this statement holds true primarily at the level of higher taxa, and is an outcome of chemical similarities among related botanical groups (Kusnezov, 1929).The generation of higher level taxonomic correlations between insects and their host plants is thought to be due to concurrent evolution. A hypothesis as to just how coevolution between insects and plants in the past resulted in these present day patterns was suggested by Brues (1920) and developed fully by Ehrlich and Raven (1965) on the basis of butterfly host plant data. The model involves adaptive radiation by plant lines which evolve effective herbivore deterrents, followed by adaptive

Conspecific mimics and low host plant availability reduce egg laying by Heliconius erato phyllis (Fabricius) (Lepidoptera, Nymphalidae)

“…Heliconians are considered to have a good sense of vision, which includes color identification and associative learning (CRANE 1955;SWIHART 1971). While aligning on hosts, females carefully inspect plant parts (BENSON et al 1976;BENSON 1978;GILBERT 1991), apparently identifying by vision the presence of conspecifics (WILLIAMS & GILBERT 1981). This was probably the case in the present study.…”

“…None of egg-bearing shoots collected from a P. suberosa population of Aguas Belas Experimental Station had more than one conspecific egg or larva, or any immature stage of other passion vine butterflies (E. Mugrabi-Oliveira, unpublished data). Field observations carried out throughout the neotropics have suggested that in general H. erato lays isolated eggs on terminal portion of several passion vine species (e.g., CRANE 1955;BENSON et al 1976;BENSON 1978;LOPES 1991;MUGRABI-OLlVEIRA & MOREIRA 1996) Egg-load assessment had already been experimentally demonstrated for another Heliconius species (WILLIAMS & GILBERT 1981). It is unknown to us whether such a discriminatorial behavior had been reported for the larval stage of heliconian butterflies.…”

“…In other words, females may have decreased their oviposition rates in the trials not only due to a decrease in number of shoots offered for oviposition, but also as a result of an increase in number of other eggs laid per shoot in such situation. To adjust oviposition rates to variation in availability of suitable host-plants for oviposition might be very important for the reproductive success of H. erato, mainly in tropical areas where passion vines may occur at relatively low densities, and where the existence offemale competition for oviposition sites among these butterflies has been suggested (BENSON et al 1976;BENSON 1978).…”

Size of and damage on shoots of Passiflora suberosa (Passifloraceae) influence oviposition site selection of Heliconius erato phyllis (Fabricius) (Lepidoptera, Nymphalidae)

“…Passion vine butterflies (Nymphalidae: Heliconiinae) are associated with a narrow range of host plants in a given location as has been observed throughout the neotropics (see BENSON et al 1976;BROWN 1981;GILBERT 1991). Oviposition preference within the range of host plants of some oligophagous heliconiine has also been experimentally demonstrated (Copp & DAVENPORT 1978;SMILEY 1978;MENNA-BARRETO & ARAUJO 1985;PERICO & ARAUJO 1991).…”

“…Oviposition preference within the range of host plants of some oligophagous heliconiine has also been experimentally demonstrated (Copp & DAVENPORT 1978;SMILEY 1978;MENNA-BARRETO & ARAUJO 1985;PERICO & ARAUJO 1991). In addition, field observations have strongly suggested that larvae of most passion vine butterflies feed preferentially on particular parts of their host plants, and that these are chosen for oviposition (see ALEXANDER 1961;BENSON et al 1976;BENSON 1978). That heliconian butterflies select hosts for oviposition based upon qualitative attributes ofthese preferred plant parts has been also suggested (BENSON et al 1976;BENSON 1978).…”