Preference for protected feeding sites by larvae of the willow‐feeding leaf beetle Galerucella lineola

Abstract

1. Free‐living insects are often thought of as more vulnerable to environmental hazards than concealed insects, such as galling or mining insects. The possibility that larvae of the free‐living leaf beetle Galerucella lineola seek out existing plant structures and thereby become partly concealed was explored. 2. Neonate larvae of G. lineola frequently feed in rolled‐in margins of young leaves of their host plant, Salix viminalis. In addition to nutritional benefits from feeding on young leaves, larvae may also gain protection against adverse weather conditions and general predators by feeding in the leaf rolls. Field and laboratory experiments were conducted to test these hypotheses. 3. Artificial shelters were constructed and cohorts of neonate larvae were placed on experimental plants. In all experiments, larvae preferred to feed in shelters, even when shelters were constructed on mature leaves. 4. In one of the experiments, fewer larvae disappeared when shelters were provided. In a predator exclusion experiment, however, no differences in predator‐inflicted mortality on G. lineola were found between shelter‐containing shoots and control shoots. 5. A laboratory experiment showed increased protection from desiccation when shelters were present; growth rate was higher for larvae feeding on plants with shelters. 6. Thus, free‐living insects may not always be as exposed to environmental hazards as is often assumed. In particular, young larvae may take advantage of preformed structures on their host plant and feed in a concealed microhabitat. Because mortality, in general, is high during early instars, shelter‐seeking behaviour may increase survival significantly. The existence of preformed shelters may therefore be a plant characteristic that should be considered when exploring the environmental risks associated with the free‐living habit.

Survivorship of Immature Stages of Eurypedus nigrosignatus Boheman (Chrysomelidae: Cassidinae: Physonotini) in Central Panama

“…A similar behavior was observed in neonate larvae of Galeruca lineóla (Galerucinae), which tend to move upward searching for physical shelter in young rolled leaves of its host plant (Larsson et al 1997). This behavior may also be due to nutritional demands, since young leaves are tender and usually contain more nutrients and water than mature leaves (Coley 1983;Ohmart et al 1985).…”

Biology and occurrence of Inga Busk species (Lepidoptera: Oecophoridae) on Cerrado host plants

“…Leaf shelters are known to protect caterpillars from predators (Damman 1987, Ruehlmann et al 1988, Loeffler 1996, to create favorable microclimates (Henson 1958, Larsson et al 1997, and to increase the quality of the leaves on which they feed. (Sagers 1992, Costa & Varanda 2002.…”

Occurrence, biology and harmfulness of Galerucella lineola (F.) (Coleoptera, Chrysomelidae) - Part 1. Last year's (parent) beetles

“…Häggström and Larsson (1995) and Kendall et al (1996) reported wintering in fissures of bark and litter (or in other hidden places). Sage et al (1999) found imagoes in aggregations (as many as 20 individuals) Larsson 1995;Larsson et al 1997). In Great Britain, imagoes colonize host plants for a period of about 2 weeks, viz from the end of March to mid-April (Sage et al 1999) or in April and May (Kendall et al 1996).…”