Chris Woolley

University of the Witwatersrand | wits · Evolutionary Studies Institute

The life cycle of almost all dung beetles revolve around mammalian dung, the feed on dung, look for mating partners on dung and lay eggs in the dung. We know they feed on dung, but we still do not understand how exactly they filter‐feed on the dung and which particles size range they are ingesting. The aim on this study was to investigate the filte...

SADIE (Spatial Analysis by Distance Indices) is designed specifically to quantify patterns in spatially-referenced count-based data. It was developed for dealing with data that can be considered ‘patchy’. Such distributions are commonly found, for example, in insect populations where discrete patches of individuals are often evident. The distributi...

Scat (faeces) decay rate estimates are used to calculate animal species abundance and density. For African great apes, this has been measured only for Gorilla; chimpanzee scats are assumed to decay at a faster rate due to lower fibre content. We provide the first systematic measure of scat decay rate duration for Pan troglodytes schweinfurthii, in...

Spiders can suppress populations of some important crop pests. Although dispersal is essential to their survival in the disturbed farmland environment, accounts of their dispersal activity over several seasons are few. Spiders dispersing across a landscape of mixed farmland were sampled over an 18-month period using Stick, Net and Bottle traps (SNB...

Two species of common, farmland-inhabiting money/dwarf spider, Erigone atra Blackwall, 1833 and Oedothorax fuscus (Blackwall, 1834), were exposed to light wind conditions within a wind chamber to determine their propensity to exhibit dispersal behaviors over a nine-month period. A novel design of wind chamber, incorporating two tangential fans, pro...

A full description is given of the first scarabaeid beetle documented from the Mesozoic (Late Cretaceous) of Africa (Orapa, Botswana). Brief and partial descriptions of this beetle have appeared in two previous review papers of fossils from the Orapa Diamond Mine. This work represents an updated analysis and interpretation of the fossil based on ch...

An understanding of spatial and temporal processes in agricultural ecosystems provides a basis for rational decision-making with regards to the management and husbandry of crops, supporting the implementation of integrated farming strategies. In this study we investigated the spatial and temporal distribution of aphid pests (Sitobion avenae and Met...

We investigated, within two cereal fields in Southern England, the within-canopy spatial distribution of the aphids Sitobion avenae and Metopolophium dirhodum in relation to crop yield and plant nitrogen. We extended the study to investigate the spatial distribution of aphids that fell to, or returned from, the ground in order to estimate availabil...

Background Dispersal plays a key role in shaping biological and ecological processes such as the distribution of spatially-structured populations or the pace and scale of invasion. Here we have studied the relationship between long-distance dispersal behaviour of a pest-controlling money spider, Erigone atra, and the distribution of maternally acqu...

An unattended trap was designed to sample and retain spiders dispersing from agricultural grassland and crops. Traps comprised a removable bottle-trap fixed to the top of a vertical metal rod or “climbing-stick” that spiders climbed during normal pre-ballooning behavior. Bottle-traps caught over eight times more spiders than sticks treated with ins...

In crop protection and ecology accurate and precise estimates of insect populations are required for many purposes. The spatial pattern of the organism sampled, in relation to the sampling scheme adopted, affects the difference between the actual and estimated population density, the bias, and the variability of that estimate, the precision. Field...

The spatial distribution of cereal aphids infesting a field of winter wheat during the population establishment, development and decline phases were studied using a field‐scale grid of sampling locations. The distribution of two generalist predators, Pterostichus melanarius and P. madidus , were sampled contemporaneously. Using spatial analysis by...

The distribution of aphid predators within arable fields has been previously examined using pitfall traps. With this technique predominantly larger invertebrate species are captured, especially Carabidae, but the technique provides no estimate of density unless mark-recapture is used. However, many other numerically important aphid predators occur...

The spatio-temporal dynamics of two aphid species (Metopolophium dirhodum and Sitobion avenae) and a generalist predator (Pterostichus melanarius) were observed in a field-scale study using a grid of 256 sampling locations with a 12-m spacing. Using Spatial Analysis by Distance Indices we demonstrate that populations show ephemeral spatial pattern...

The efficiency of barrier-connected pitfall trapping was compared to conventional single traps or arrays. For ground-active beetles, the use of a pitfall system incorporating a wetting agent with five traps arranged in a cross formation connected by plastic barriers was more efficient than a single dry trap by at least an order of magnitude and at...

The work described in this paper characterises the spatial and temporal distributions of aphids and their natural enemies in winter wheat. Three uses of these data are presented, which investigate; firstly, the possible effectiveness of precision-based spatially varied pesticide application; secondly, crop-scouting strategies; and thirdly, predator...

An experiment was conducted to measure the effects of summer warming on the total population densities of soil-dwelling microarthropods in the high Arctic and to compare these results with those from natural between-year and between-site variations. Small polythene tents were used to elevate summer temperatures over 3 years on polar semi-desert and...