Host plant finding in the specialised leaf beetle Cassida canaliculata: an analysis of small‐scale movement behaviour

Abstract

Abstract. Host plant finding in walking herbivorous beetles is still poorly understood.Analysis of small-scale movement patterns under semi-natural conditions can be a useful tool to detect behavioural responses towards host plant cues.In this study, the small-scale movement behaviour of the monophagous leaf beetle Cassida canaliculata Laich. (Coleoptera: Chrysomelidae) was studied in a semi-natural arena (r = 1 m). In three different settings, a host (Salvia pratensis L., Lamiales: Lamiaceae), a non-host (Rumex conglomeratus Murr., Caryophyllales: Polygonaceae), or no plant was presented in the centre of the arena.The beetles showed no differences in the absolute movement variables, straightness and mean walking speed, between the three settings. However, the relative movement variables, mean distance to the centre and mean angular deviation from walking straight to the centre, were significantly smaller when a host plant was offered. Likewise, the angular deviation from walking straight to the centre tended to decline with decreasing distance from the centre. Finally, significantly more beetles were found on the host than on the non-host at the end of all the trials.It is concluded that C. canaliculata is able to recognise its host plant from a distance. Whether olfactory or visual cues (or a combination of both) are used to find the host plant remains to be elucidated by further studies.

Olfactory versus Contact Cues in Host Plant Recognition of a Monophagous Chrysomelid Beetle

“…A recent study by Heisswolf et al (2007) showed that C. canaliculata beetles could find their host plant from a distance of at maximum 50 cm, when a plant individual was offered in a semi-natural arena. However, whether visual or olfactory cues alone or in combination attracted the beetles could not be discriminated.…”

“…Within Germany, C. canaliculata is endangered, in Bavaria it is even threatened by extinction (Kippenberg, 2003); however, on warm slopes in the nature reserve 'Hohe Wann' in Northern Bavaria, Germany (50 • 03' N, 10 • 35' E), it is locally abundant (A. Heisswolf and E. Obermaier, personal observations). Only few details are published on the ecology of C. canaliculata (Steinhausen, 1949;Trautner et al, 1989;Heisswolf et al, 2005Heisswolf et al, , 2006Heisswolf et al, , 2007, and little is known about the host recognition pro-Journal of Insect Behavior (2007) 20:247-266 cess in this species. However, as monophagous herbivores the beetles should be very specifically able to recognize their host plant species S. pratensis.…”

Modeling caterpillar movement to guide habitat enhancement for Speyeria zerene hippolyta, the Oregon silverspot butterfly

“…Cain 1985;Crist et al 1992;Turchin 1998;Goodwin and Fahrig 2002;Potting et al 2005;Chapman et al 2007;Heisswolf et al 2007;Roslin et al 2008). Modeling was simplified by the fact that the presence of food plants does not induce a bias in the movement of searching larvae ).…”

Locating host plants via orientation to standing visual targets has dispersal benefits for the monophagous leaf beetle Ambrostoma quadriimpressum

“…Screenshots from the video of each beetle's movements were taken every 3 s and overlain to obtain an image of its walking track, which was converted to top view using Adobe Photoshop 10.0 (San Jose, CA, USA). The straightness of each beetle's movements was then calculated as the ratio between the vector length (from start to end point) to track length, which can range from 0 to 1 (Visser, ; Heisswolf et al., ). Each beetle's track length was measured using Autocad (2007) software (San Rafael, CA, USA), whereas the vector length was a constant 1.5 m (from the center to the edge of the test arena).…”