Walking behaviour in the ground beetle,Poecilus cupreus: dispersal potential, intermittency and individual variation

Abstract

Dispersal is a key ecological process affecting community dynamics and the maintenance of populations. There is increasing awareness of the need to understand individual dispersal potential to better inform population-level dispersal, allowing more accurate models of the spread of invasive and beneficial insects, aiding crop and pest management strategies. Here, fine-scale movements of Poecilus cupreus, an important agricultural carabid predator, were recorded using a locomotion compensator and key movement characteristics were quantified. Net displacement increased more rapidly than predicted by a simple correlated random walk model with near ballistic behaviour observed. Individuals displayed a latent ability to head on a constant bearing for protracted time periods, despite no clear evidence of a population level global orientation bias. Intermittent bouts of movement and non-movement were observed, with both the frequency and duration of bouts of movement varying at the inter- and intra-individual level. Variation in movement behaviour was observed at both the inter- and intra- individual level. Analysis suggests that individuals have the potential to rapidly disperse over a wider area than predicted by simple movement models parametrised at the population level. This highlights the importance of considering the role of individual variation when analysing movement and attempting to predict dispersal distances.

“Micropersonality” traits and their implications for behavioral and movement ecology research

“…A subsampling rate of 2.5 Hz was used to prevent false large turns which can occur due to the processing of the video recording (Delcourt et al, 2013). The movement threshold and subsampling rates are in essence arbitrary values but were chosen to retain as much information about the movement path, while minimizing any causal effects such smoothing can have on characteristics of movement trajectories (Bailey et al, 2020;Benhamou, 2014;Bovet & Benhamou, 1988;Codling & Hill, 2005;Gurarie & Ovaskainen, 2011); different combinations of thresholds and subsampling did not affect our findings (Figures S2-S10).…”

Simulating capture efficiency of pitfall traps based on sampling strategy and the movement of ground‐dwelling arthropods

“…For instance, activity levels can vary if beetles are starved or satiated (Fournier & Loreau, 2001; Grüm, 1971), intermittency, e.g. periods of rest (Bailey et al, 2021), habitat characteristics (Allema et al, 2014; Goodwin & Fahrig, 2002; Růžičková & Veselý, 2018), possible competition with other species (Růžičková et al, 2021). We estimated that for P. melanarius , trap counts are maximised over a narrow diffusive range between D = 0.28 m 2 /h, S = 2.74 ( c = 0.6) and 0.61 m 2 /h, S = 1.86 ( c = 0.8).…”

“…The turning angle α i can then be measured as the difference between the orientations of two successive steps α i = 𝜃 i − 𝜃 i− 1 , and the individual movement trajectory can be simulated given that the probability distributions of l and α are prescribed. The RW framework for modelling arthropod movement is an idealisation (Figure 1), which is commonly used in the literature (Bailey et al, 2021; Kareiva & Shigesada, 1983; Miller et al, 2015; Turchin, 1998).…”

“…For purposes of interpretation and to provide ecological context, we consider the ground beetle P. melanarius (Illiger, 1798) as a model species, which is a close representative of other carabid species from the same genus (Raupach et al, 2020) and some other beetles with similar biological and physical traits, e.g. Poecilus cupreus (Linnaeus, 1758) (Bailey et al, 2021). P. melanarius is distributed across Europe and Asia, often occurring in high abundances and being a dominant ground beetle species especially in agricultural landscapes (e.g.…”

“…CRWs have been used to model the movement of several ground‐dwelling arthropods, e.g. ants, beetles (Bailey et al, 2021; Byers, 2001; Reynolds et al, 2013). By simulating the random movement of ground‐dwelling arthropods, and computing trap counts as frequency of encounters with virtually placed traps, it is possible to analyse the direct effect of movement such as diffusion and tortuosity (i.e.…”