Is a mango just a mango? Testing within-fruit oviposition site choice and larval performance of a highly polyphagous fruit fly

Abstract

For fruit flies, fully ripe fruit is preferred for adult oviposition and is superior for offspring performance over unripe or ripening fruit. Because not all parts of a single fruit ripen simultaneously, the opportunity exists for adult fruit flies to selectively choose riper parts of a fruit for oviposition and such selection, if it occurs, could positively influence offspring performance. Such fine scale host variation is rarely considered in fruit fly ecology, however, especially for polyphagous species which are, by definition, considered to be generalist host users. Here we study the adult oviposition preference/larval performance relationship of the Oriental fruit fly, Bactrocera dorsalis (Hendel) (Diptera: Tephritidae), a highly polyphagous pest species, at the ''within-fruit'' level to see if such a host use pattern occurs. We recorded the number of oviposition attempts that female flies made into three fruit portions (top, middle and bottom), and larval behavior and development within different fruit portions for ripening (color change) and fully-ripe mango, Mangifera indica L. (Anacardiaceae). Results indicate that female B. dorsalis do not oviposit uniformly across a mango fruit, but lay most often in the top (i.e., stalk end) of fruit and least in the bottom portion, regardless of ripening stage. There was no evidence of larval feeding site preference or performance (development time, pupal weight, percent pupation) being influenced by fruit portion, within or across the fruit ripening stages. There was, however, a very significant effect on adult emergence rate from pupae, with adult emergence rate from pupae from the bottom of ripening mango being approximately only 50% of the adult emergence rate from the top of ripening fruit, or from both the top and bottom of fully-ripe fruit. Differences in mechanical (firmness) and chemical (total soluble solids, titratable acidity, total nonstructural carbohydrates) traits between different fruit portions were correlated with adult fruit utilisation. Our results support a positive adult preference/offspring performance relationship at within-fruit level for B. dorsalis. The fine level of host discrimination exhibited by B. dorsalis is at odds with the general perception that, as a polyphagous herbivore, the fly should show very little discrimination in its host use behavior.

Five commercial citrus rate poorly as hosts of the polyphagous fruit fly Bactrocera tryoni (Froggatt) (Diptera: Tephritidae) in laboratory studies

“…A similar result was reported by Rattanapun et al . (), who found that adult emergence from pupae that had developed from mature green mango was only half of that of pupae originating from fully ripe mango. Potential limits in larval di et al so appear to flow on to the subsequent adults with, for example, no eggs collected from the 23 female flies reared from grapefruit.…”

Memory duration is positively correlated with host fruit preference and offspring performance in a polyphagous frugivore

“…2001; Fontellas‐Brandalha and Zucoloto 2004; Hannah and Zalom 2008; Rattanapun et al . 2010), positive preference/performance relationships have been demonstrated, but this relationship is not universal across frugivorous tephritids (Fitt 1986; Fernandes‐Da‐Silva and Zucoloto 1993; Balagawi et al . 2013) and should not be automatically assumed.…”

Oviposition of fruit flies (Diptera: Tephritidae) and its relation with the pericarp of citrus fruits

“…Prokopy and Vargas (1996) believe that epicarp thickness of citrus fruits could be an important criterion in infestation of fruit flies. Thus, the host range of tephritid fruit flies may be restricted by the ability of the insect to penetrate the peel of the host fruit (Rattanapun et al, 2009(Rattanapun et al, , 2010. Thus, this study investigated oviposition of A. fraterculus and C. capitata and its relation with the pericarp of citrus fruits.…”