A tritrophic analysis of host preference and performance in a polyphagous leafminer

Abstract

The optimal oviposition theory predicts that oviposition preferences of phytophagous insects should correlate with host suitability for their offspring. As plant host suitability depends not only on its quality as food, but also on its provision of enemy‐free space, we examined the relationship between adult host preference and offspring performance for the leafminer Liriomyza huidobrensis (Blanchard) (Diptera: Agromyzidae) on various host plants, considering also the interaction with natural enemies. Preference and offspring performance were assessed through observational field data and laboratory experiments in central Argentina. Field data suggested a positive host preference – performance linkage, as the leafminer attained larger body size on the crops where it was more abundant. Laboratory trials supported these results: Vicia faba L. (Fabaceae) was the preferred host in the laboratory as well as in the field, performance of L. huidobrensis being also best on this host, with highest survival rates and shortest development time. The actively feeding larval stage showed the largest plant‐related effects. Higher overall parasitism rates were found on plants from which smaller leafminers were reared, reinforcing the preference–performance linkage. On the other hand, the main parasitoid Phaedrotoma scabriventris Nixon (Hymenoptera: Braconidae) reached larger body size, and caused higher mortality rates on crops where the leafminer was larger. Changes in abundance of particular parasitoid species could thus modify overall parasitism trends.

Choosing between good and better: optimal oviposition drives host plant selection when parents and offspring agree on best resources

“…Enemy-free space might provide a secondary, weaker factor to host plant quality in determining the pattern of host use for L. huidobrensis. In a previous study dealing with a wider host range than the two species considered here, leafminer abundance was higher on host plants were individuals attained bigger body size, developed faster, and parasitism rates were lower (Videla et al 2006). Here, also, parasitism rates tended to be higher when the leafminer developed on B. v. var.…”

“…The parasitoid community of L. huidobrensis in the study region includes 16 species in the Eulophidae, Pteromalidae, Eucoilidae, and Braconidae families Valladares 1995, 1999;Salvo et al 2005, Videla et al 2006.…”

“…Eggs are inserted into the mesophyll and the emerging larvae feed on the spongy mesophyll while excavating typical serpentine mines (Parrella et al 1985), Wnally exiting the leaf to pupate in the soil. The life cycle can be completed in 14-57 days depending on temperature (Head et al 2002) and host plant (Videla et al 2006).…”

“…This polyphagous and widely distributed leafminer pest (Dempewolf 2004) attacks several crops in central Argentina and consistently occurs at higher densities on some of them (Salvo and Valladares 1995;Valladares et al 1996Valladares et al , 1999. Females have been shown to select between plants at opposite extremes of the leafminer host ranking, those providing higher performance to their oVspring, although no adult performance variables were measured (Videla et al 2006). Moreover, the ovipositing females can even discriminate between their two top ranked local host plants (Videla et al 2010).…”

Liriomyza commelinae(Diptera: Agromyzidae): an alternative host for parasitoids of the leafminer pestLiriomyza huidobrensis

“…C. flacilla, D. websteri, and A. enneatoma) cause a great impact on the pest species. In addition to causing high rates of parasitism of L. commelinae, they have been reported as efficient mortality agents of L. huidobrensis, which was found feeding on several horticultural crops in Argentina (Salvo and Valladares 1995;Videla et al 2006). Diglyphus begini, a congeneric species of D. websteri, has been repeatedly used for inoculative and inundative releases in greenhouses against L. trifolii and other Liriomyza species (Heinz and Parrella 1990;Cure and Cantor 2003).…”