Host plant preferences of Uresiphita reversalis (Guenée) (Lep., Crambidae)

Abstract

Uresiphita reversalis Guenee (Lep., Crambidae) is a North American species whose native hosts include legumes (Fabaceae) in the genera, Lupinus L. (Genisteae, Lupininae), Baptisia Vent. (Thermopsidae) and Sophora L. (Sophoreae). Several species from the Genisteae, subtribe Genistinae, have been introduced to the United States and U. reversalis has expanded its host range to include these species. Members of all of these tribes bear quinolizidine alkaloids (QA). Ovipositional and larval preferences of U. reversalis for both introduced and native species were examined. Adults and larvae prefer Genista L. and thus preference is proposed to be indirectly or directly associated with the presence of QA with higher toxicity in this genus than in other host genera. Larvae of U. reversalis are known to sequester QA, which are deterrent and toxic to their natural enemies.

Benefits of gregarious feeding by aposematic caterpillars depend on group age structure

“…We noted the relative frequencies of different larval ages (as determined initially by mass and subsequently by instar) and found these to be highly variable among hosts (Online Resource 1). While some variation in development would be expected among larvae, the highly variable age structure we observed could only have resulted from females ovipositing sequential clutches on the same hosts, as noted by Leen (1998). Based on these observations, and the low overall percentage of colonized plants (ca.…”

“…first and sixth instars; Online Resource 1) suggests that repeated oviposition is the proximate cause of mixedage gregariousness, an hypothesis supported by laboratory experiments with this species (Leen 1998). Several other species of lepidopteran herbivores also show preferential or gregarious oviposition on hosts with eggs or larvae already present (Francini and Lucci Freitas 2010;Reed 2003;Ulmer et al 2003), while some species avoid previously attacked plants (Vasconcellos-Neto and Monteiro 1993).…”

“…The gregariousness appears to result in part from the deposition of large (though variable) clutches of eggs (Leen 1995). Moreover, plants in the field appear to receive sequential clutches of eggs despite the presence of alternative, unattacked hosts (Leen 1998), and females prefer to oviposit on previously preferred hosts in laboratory assays (Leen 1998). While this preference is indirect evidence for an adaptive value of gregariousness (Jaenike 1978), the actual benefit of this behaviour has not been tested in a manipulative experiment.…”

“…The herbivore, larvae of the genista moth, Uresiphita reversalis (Lepidoptera: Crambidae) (Fig. 1), is oligophagous, feeding on species in quinolizidine-alkaloid-containing tribes of the Fabaceae (Leen 1997), though appearing restricted to L. diffusus at ABS. Larvae sequester host alkaloids as an anti-predator defence (Montllor et al 1990) and are aposematically coloured with black, white and chartreuse markings.…”

Dietary Challenges for Parasitoid Wasps (Hymenoptera: Ichneumonoidea); Coping with Toxic Hosts, or Not?

“…Members of the genus Uresiphita (Lepidoptera: Crambidae) appear to be specialists on various quinolizidine alkaloid-containing members of Fabaceae [ 189 ]. The N. American broom moth, Uresiphita reversalis [ 132 ], is cryptic as an adult, but its larvae are aposematic on their broom host plant, Genista monspessulana (Fabaceae: Genista ).…”