Individual Mobility Prevents an Allee Effect in Sparse Populations of the Bush Cricket Metrioptera roeseli: An Experimental Study

Does wing dimorphism affect mobility in Metrioptera roeselii (Orthoptera: Tettigoniidae)?

“…The percentages of marked individuals seen again are comparable with those recorded in other studies on Orthoptera (Heller & von Helversen, 1990;Kindvall et al, 1998;Diekötter et al, 2005Diekötter et al, , 2007. Marking with reflective material has resulted in day-to-day percentages of individuals seen again of more than 80% (Hein et al, 2003;Heidinger et al, 2009).…”

“…Maes et al, 2006;Walters et al, 2006;Heidinger et al, 2009). However, there are several studies that record no differences between sexes (Kindvall, 1999;Brunzel, 2002;Diekötter et al, 2005), including the study on M. roeselii carried out by Kindvall et al (1998). At 9.0 m for males and 7.8 m for females, the mean daily movement values recorded by Kindvall et al (1998), however, are similar to the results presented here (males: 9.9 m, females: 7.3 m).…”

“…Although the mobility of many species of Orthoptera has been studied (Kindvall et al, 1998;Leisnham & Jamieson, 2002;Hein et al, 2003;Gardiner & Hill, 2004;Diekötter et al, 2005), nothing is known about the locomotory behaviour of macropters. Indeed, observations on the flight of long-winged individuals suggest that this morph is much more mobile than its short-winged conspecifics (Higaki & Ando, 2003;Smith, 2007;Gardiner, 2008).…”

Influence of linear versus network corridors on the movement and dispersal of the bush-cricket Metrioptera roeseli (Orthoptera: Tettigoniidae) in an experimental landscape

“…The area of suitable habitat surrounding an individual positioned in a node is greater than for an individual positioned in a corridor; for male bush-crickets, this means that nodes offer a greater area for attracting females by stridulating. If so, one prediction is that nodes may also be attractive for females, as encounters with mates would increase and the male-male competition in these areas would ensure that average quality of the males at nodes was higher than in corridors (Kindvall et al, 1998;Gascoigne et al, 2009). If these findings are transferrable to larger scales, nodes could have positive effects at the population level by increasing the possibility of: (1) finding new habitats in a varying environment and (2) increased mate choice.…”

“…Our aim was to examine the potential role of nodes in influencing the movement of male M. roeseli within these linear elements, rather than between larger habitat patches, because these linear elements constitute a large proportion of the total habitat area utilized by M. roeseli within the agricultural landscapes of central Sweden, where this species is currently increasing in abundance (Berggren et al, 2001). We expected that when presented with a node-rich landscape, individuals would: (1) utilize the nodes to change their general direction of movement (de Jong & Kindvall, 1991), (2) after an initial period of exploration, be more likely to be located in and around nodes than within the linear habitat elements linking nodes (Kindvall et al, 1998), and (3) have lower rates of emigration from a node-rich landscape than a Single landscape. We used the Single landscape as a control for interpreting any distribution patterns found within the Lattice landscape for example, if bush-crickets aggregated at the first node they encountered, was this because of some intrinsic quality of the node or a function of a simple stopping rule based on distance.…”