The role of plant trichomes and caterpillar group size on growth and defence of the pipevine swallowtail Battus philenor

By J. Fordyce, A. Agrawal. 2001

173 citations recorded by the source corpus.

Summary 1. The California population of the pipevine swallowtail Battus philenor is a specialist on the Dutchman’s pipe Aristolochia californica , an endemic vine that is densely covered with trichomes. Populations of B. philenor outside California use other Aristolochia species that are largely glabrous. The average clutch size of the pipevine swallowtail is larger in California compared with populations elsewhere and larvae feed gregariously until late in the third instar. 2. In the field, caterpillars consumed more leaf material and showed preference for portions of leaves with trichomes removed. However, large groups of caterpillars were consistently observed feeding on the apical portion of the plant, where trichome density was highest. Smaller groups of caterpillars were observed feeding more often on mature leaves on the lower portions of the plant, where trichome density was lower. 3. Laboratory experiments showed that the walking speed of a commonly observed predator, larvae of the green lacewing Chrysopa carnea , was reduced as trichome density increased. Furthermore, lacewing search efficiency and capture rate of a model prey item were compromised by high trichome density. 4. In an additional field experiment, no difference was found in the percentage mortality of groups of four and 12 caterpillars. However, growth rate of the larger group was accelerated by 25% compared with smaller groups. In an experiment using a ladybird beetle larva Hippodamia convergens as the predator, no difference was observed in absolute mortality of caterpillars, suggesting that group size does not function directly as a defence against predators. 5. First instar caterpillars are most vulnerable to predators, thus feeding in larger groups may benefit caterpillars by accelerating growth. Feeding in large groups may also be an effective strategy for B. philenor to overcome plant trichomes and feed on portions of the plant conducive to faster development. However, feeding on areas with dense trichomes does not appear to provide larvae with a refuge from predators.

Subfields: Ecology, Ecology, Evolution, Behavior and Systematics, Insect Science

View Paper: https://www.semanticscholar.org/paper/e96e3bbfbde466f302568b2c807c997e4799ae06

How researchers see this paper

The researchers whose trusted networks rank it highest, strongest advocate first. Every researcher gets a different order.

In Ecology

In Ecology, Evolution, Behavior and Systematics

In Insect Science

Citations in the corpus

Plant surface–bug interactions: Dicyphus errans stalking along trichomes (2007, background): “…Sphingidae, Noctuidae, Tetranychidae), based mainly on the presence of trichomes (Lee et al. 1986; Haddad and Hicks 2000), their density (e.g. Fordyce and Agrawal 2001; Kowalewski and Robinson 1978; Zvereva et al. 1998; Rudgers et al. 2004), shape (Andres and Connor 2003), length (Hoxie et…”
Safety in numbers: the dilution effect and other drivers of group life in the face of danger (2016, background): “More generally, several empirical studies have failed to find an effect of group size on per capita survival (Le Masurier 1994; Fordyce and Agrawal 2001; Lindstedt et al. 2006, 2011).”
Feeding by lepidopteran larvae is dangerous: A review of caterpillars’ chemical, physiological, morphological, and behavioral defenses against natural enemies (2012, background): “1972; DeVries, 1987, 1997; Allen, 1990; Clark and Faeth, 1997; Fordyce and Agrawal, 2001) (Figs 7ad, 8a, c) and, in some, has been shown to be an effective defense against a variety of enemies (Myers and Smith, 1978; Lawrence, 1990; Parry et al., 1998; McClure and Despland, 2011).”
Leaf Trichome Formation and Plant Resistance to Herbivory (2008, background): “In most empirical studies, the abundance and effectiveness of natural enemies were found to be negatively correlated with the density of plant trichomes (Kauffman and Kennedy 1989; Farrar and Kennedy 1991; Nihoul 1993; Gange 1995; Heinz and Zalom 1996; Romeis et al. 1998, 1999; Krips et al. 1999; Ro”
Plant structural traits and their role in anti-herbivore defence (2007, background): “Although trichomes reduce caterpillar feeding by up to 70%, they also reduce movement of the predatory lacewing, Chrysopa carnes, offering Battus larvae some protection against predation (Fordyce and Agrawal, 2001).”
Plant Defense against Insect Herbivores (2013, background): “Removal of trichomes results in increased feeding and growth of herbivorous insects [303].”