Power laws are increasingly used to describe animal movement. Despite this, the use of power laws has been criticized on both empirical and theoretical grounds, and alternative models based on extensions of conventional random walk theory (Brownian motion) have been suggested. In this paper, we analyse a large volume of data of aphid walking behaviour (65,068 data points), which provides a high...

1. The interaction between 'migratory flight', defined as flight oriented vertically and horizontally towards a large overhead light source, and 'targeted flight' oriented towards a yellow leaf-like object seen to one side against a dark background, has been analysed in Aphis fabae in a laboratory flight chamber. Landings were prevented by regulating a down-current of air so as to balance the f...

Study of mechanisms responsible for regulating populations of living organisms is essential for a better comprehension of the structure of biological communities and evolutionary forces in nature. Aphids (Hemiptera: Sternorrhyncha) comprise a large and economically important group of phytophagous insects distributed worldwide. Previous studies determined that density-dependent mechanisms play ...

*Unité de Recherches Avicoles, Fonction et Régulation des Protéines de l’oeuf, INRA, 37380 Nouzilly, France, UMR INRA -AgroCampus Rennes 1253 Science et Technologie du Lait et de l'Oeuf, 65 rue de Saint-Brieuc, 35042 Rennes Cedex, France, Max-Planck-Institut für Biochemie, Abteilung für Proteomics und Signaltransduktion, Martinsried, Germany, Department of Cellular and Molecular Medicine, Unive...

Soybean aphid (Aphis glycines Matsumura) is a severe pest of soybean in central North America. Outbreaks of the aphid in Ontario are often spotty in distribution, with some geographical areas affected severely and others with few or no aphid populations occurring in soybean for the duration of the season. A. glycines spend summers on soybean and overwinter on buckthorn, a shrub that is widespre...

Ants often form mutualistic interactions with aphids, soliciting honeydew in return for protective services. Under certain circumstances, however, ants will prey upon aphids. In addition, in the presence of ants aphids may increase the quantity or quality of honeydew produced, which is costly. Through these mechanisms, ant attendance can reduce aphid colony growth rates. However, it is unknown ...

The most famous epistemic paradox is Fitch’s paradox. In it, Frederic Fitch offered a counterexample to the Principle of Knowability (PK), namely, that any true proposition can be known. His example is the proposition that some proposition is true but not known. This proposition is not paradoxical or contradictory in itself, but contradicts (PK), which many have found appealing. What is really ...

Complete coding regions of the 18S rRNA gene of an enteropneust hemichordate and an echinoid and ophiuroid echinoderm were obtained and aligned with 18S rRNA gene sequences of all major chordate clades and four outgroups. Gene sequences were analyzed to test morphological character phylogenies and to assess the strength of the signal. Maximum-parsimony analysis of the sequences fails to support...

Half-root tests were established to examine the association between Heterodera glycines and the blue strain of Fusarium solani, the causal agent of sudden death syndrome (SDS) of soybean. Two independent root systems were established for soybean 'Coker 156' and inoculated (half root/half root) with F. solani, H. glycines, both organisms on opposite root halves, both organisms on one root half, ...

Lepidopteran types of podborer and homopteran aphid insects are damaging pests of chickpea. CryIAc toxins are established control agents for podborers but do not or only slightly affect homopteran (sucking) insects. However, certain plant lectins are known for their power of killing aphids. Bioassay experiments carried out in our laboratory with lectins isolated from garlic leaves have already ...