Plant surface–bug interactions: Dicyphus errans stalking along trichomes

Abstract

In contrast to many arthropods whose locomotion on plant surfaces is impeded by trichomes, the omnivorous mirid bug Dicyphus errans Wolff (Heteroptera, Miridae, Bryocorinae) lives on pubescent plants and preys on a variety of phytophagous arthropods. Morphological (slim body, long slender legs, elongated curved claws) and behavioural (locomotion) adaptations to hairy plant substrates result in higher predation effectiveness and fecundity, as well as a shorter developmental cycle of the bug compared to insects on plants without trichomes. To understand the bug-plant interactions from the biomechanical point of view, the bug's attachment system and the leaf surfaces of various plant species were analysed. Bug attachment ability was estimated in an inversion experiment on the adaxial and abaxial sides of leaves in 40 plant species. Furthermore, bug traction forces on the abaxial leaf side of 14 plant species were measured. Morphometrical variables of trichomes and the adhesive properties of plant surfaces were estimated. The bugs' traction force ranged from 0.07 mN on Brassica oleracea (Brassicaceae) to 1.21 mN on Plectranthus ambiguus (Lamiaceae) and Solanum melongena (Solanaceae). Bugs performed considerably better on hairy surfaces where a significant positive correlation between the force and both the trichome length and diameter was found. The trichome density and aspect ratio did not influence the force. Adhesion properties of plant surfaces covered with trichomes may also significantly impede the traction force. Based on the results obtained, it is concluded that hairy plants provide a more suitable environment for D. errans than either smooth ones or those covered with wax crystals. Hairy plant surfaces are predicted to support stronger attachment and therefore more reliable locomotion of the bug.

Tomato-aphid-hoverfly: a tritrophic interaction incompatible for pest management

“…The latter prefers to oviposit on plants having glandular trichomes that would provide the eggs a refuge from cannibalism and other predation. The omnivorous mirid bug Dicyphus errans Wolff (Heteroptera, Miridae) preys on a variety of phytophagous arthropods living on pubescent plants that provide the bug stronger attachment and therefore more reliable locomotion as well as more successful oviposition and predation (Voigt et al 2007). The contrary observations realized in our study with E. balteatus may be caused by different morphological features.…”

“…But furthermore, the type, arrangement, dispersion, anatomy properties, and geometrical variables of trichomes may influence insect attachment to and locomotion on plant surfaces (e.g. Voigt et al 2007). In particular, sticky exudates of glandular trichomes may contaminate insects (Kennedy 2003;Voigt et al 2007), which may be also possible in E. balteatus contacting glandular hairy plant surfaces.…”

Attachment force of the beetle Cryptolaemus montrouzieri (Coleoptera, Coccinellidae) on leaflet surfaces of mutants of the pea Pisum sativum (Fabaceae) with regular and reduced wax coverage

“…Excellent attachment ability on various smooth artificial and natural surfaces has been previously reported for many insects (Way and Murdie 1965;Stork 1980;Edwards 1982;Eigenbrode 1996;Federle et al 2000;Gorb 2002, 2006a). In waxy plant substrates, the deteriorative effect of the crystalline wax coverage on insect attachment has been experimentally shown by many authors (Stork 1980(Stork , 1986Edwards 1982;Bodnaryk 1992;Eigenbrode 1996;Eigenbrode et al 2000;Federle et al 2000;Eigenbrode and Jetter 2002;Gaume et al 2002Gaume et al , 2004Gorb et al 2005;Voigt et al 2007). It has been found for several insect species and a series of plant species that insects can attach well to smooth substrates, without wax or with removed wax bloom, whereas they fail on waxy surfaces.…”

“…This effect can be explained by removal of the microroughness caused by wax crystals and probably by a strongly increased surface roughness, enabling beetles to use their claws for mechanical interlocking with the surface (Dai et al 2002;Gorb et al 2005;Voigt et al 2007). In addition, surfaces with large roughness provide enough smooth sites for proper contact formation by single spatulae of adhesive hairs.…”

“…Regarding the latter function, it has been previously repeatedly reported that plant surfaces, bearing crystalline wax coverage, reduce the attachment of insects (Stork 1980(Stork , 1986Edwards 1982;Bodnaryk 1992;Eigenbrode 1996;Eigenbrode et al 2000;Federle et al 2000;Eigenbrode and Jetter 2002;Gaume et al 2002Gaume et al , 2004Gorb et al 2005;Voigt et al 2007). In some of these studies, conducted with different insect and plant species, it has been experimentally shown that insects were able to attach successfully to smooth substrates, without wax or with removed wax, but failed on pruinose surfaces.…”