Intraspecific aggression, colony identity and foraging distances in Sudanese Microtermes spp. (Isoptera: Termitidae: Macrotermitinae)

Abstract. 1. Intraspecific aggression between termite major workers was used to obtain estimates of foraging distances for three Microtermes species in Sudan.
2. Maximum foraging distance recorded for M. sp. nr albopartitus (Sjöstedt) in Khartoum was 11.3 m, giving an estimated minimum colony area of 100 m². This is probably an underestimate. In the Tokar Delta, individuals from single colonies of M. najdensis Harris were encountered up to 42 m apart, giving a colony area of 1390 m².
3. Intraspecific aggression could not be used reliably to distinguish members of different colonies of M. lepidus Sjöstedt. Soil barrier formation between groups of workers in petri dishes may be of use as a supplementary technique, especially for species showing no clear aggression.
4. Experiments on isolated laboratory colonics of M. sp. Nr lepidus Sjöstedt, established from alates collected in Khartoum, further confirmed the value of inter-colony aggression for indicating colony identity.
5. The complications introduced into estimation of subterranean termite foraging areas by overlap and interdigitation of colonies are discussed.     

Determination of the Volume and Surface Area of Tetrahymena pyriformis,and their Relationship to Endocytosis*

Methods are described for the determination of the mean cellular volume and surface area of Tetrahymena pyriformis GL by direct microscopic measurement or by Coulter counter. The results are compared and discussed. It is suggested that the latter is the more accurate method of estimation. Fed cells showed a bimodal size distribution by Coulter counter determination and had a mean volume of 10,000–11,000 μM³, whereas cells which had been starved for 1 or 2 days showed a unimodal distribution and had mean cellular volumes of ～ 1,600 and 1,200 μ³ respectively. The corresponding mean surface areas were ～ 1,900, 550 and 450 μM² respectively. The discrepancy between the results of the 2 methods of estimation was greater with starved than with fed cells because of the greater asymmetry of the former. Continued cell division during the early part of the starvation period had a considerable reducing effect upon the mean cellular volume, but other unidentified factors were also important in producing the observed diminution in volume. Comparison of the mean surface areas of starved cells with previously recorded rates of membranous utilization in endocytosis upon refeeding indicate that insufficient cell membrane was present to maintain the rates of vacuole formation observed.     

Gnidia (Thymelaeaceae) is not monophyletic: taxonomic implications for Thymelaeoideae and a partial new generic taxonomy for Gnidia

We address the generic limits of Gnidia (Thymelaeaceae) through a phylogenetic analysis of nuclear ribosomal DNA internal transcribed spacer (ITS) and plastid rbcL, trnL intron and trnL‐F intergenic spacer regions. Maximum parsimony and Bayesian inference were used to produce trees and assess internal support. The most significant conclusion drawn from the molecular analysis is that Gnidia is polyphyletic as currently circumscribed, comprising at least four distinct lineages that are each related to other genera within Thymelaeoideae. Gnidia pinifolia and G. racemosa are members of a clade within which Struthiola is embedded; a second group of species allies with Drapetes as sister to Passerina; and a third lineage corresponds to the previously recognized genus Lasiosiphon. The remaining species of Gnidia included in this study are allied with the Australian genus Pimelea. The taxonomic implications of these findings are discussed in relation to the principle of monophyly. © 2009 The Linnean Society of London, Botanical Journal of the Linnean Society, 2009, 160 , 402–417.     

Effects of Pollutants on Molting and Regeneration in Crustacea

Many environmental pollutants have toxic effects that can alternormal limb regeneration and molting in Crustacea. The mostcommon effect of heavy metals is that of retardation of regenerationof limbs accompanied by a delay in ecdysis; in some cases regenerationis affected without altering the molt cycle. Chlorophenols anddithiocarbamates caused inhibition of regeneration without affectingmolting in shrimp. Organic toxicants such as aromatic hydrocarbonsanddioxins also result in a decrease in the growth increment permolt, while DDT was found to accelerate regeneration and molting.A number of toxicants also produce morphological alterationsin the regenerated limbs of crabs. These may be relatively minor,such as reduced number of pigment cells, setae, or tuberclesin the regenerated limbs (mercury and cadmium), or may be moremajor deformities, such as abnormal bending in the limb or claw(tributyltin), or defects inchitin formation in the exoskeleton(diflubenzuron).     

A New Organelle of Bloodstream Salivarian Trypanosomes

SYNOPSIS. Electron micrographs of the bloodstream forms of Trypanosoma brucei, T. congolense and T. vivax revealed a group of 4 subpellicular microtubules lying near the point of attachment of the flagellum and associated with a vesicular membrane which, in T. brucei at least, is continuous with the outer nuclear membrane. Since its function is unknown, the whole structure is provisionally termed the "subpellicular organelle."     

The Biology of Haemogregarina bigemina Laveran & Mesnil, a Parasite of the Marine Fish Blennius pholis Linnaeus

SYNOPSIS. Haemogregarina bigemina was found in all Blennius pholis which exceeded 5.0 cm in length, but in none measuring less than 3.5 cm. No exoerythrocytic development was recorded. The first B. pholis eggs hatched in May while the first patent infections of H. bigemina occurred from September onward in metamorphosed fish. Consequently, if the life cycle of H. bigemina includes a vector, that organism is active between May and September at least. Circumstantial evidence indicates that the hematophagous isopod, Gnathia maxillaris and not leeches, could be a vector of H. bigemina. Developmental stages of sporozoa were found in a small number of the isopods which had fed on infected B. pholis but the parasites could not be identified as H. bigemina with certainty. Subcellular organization, typical of sporozoa, was recorded by electron microscopy of H. bigemina.     

Re‐contemplate an entangled bank: The Power of Movement in Plants revisited

We review the ways in which two of Charles Darwin's lesser known works, The Movement and Habit of Twining Plants and The Power of Movement in Plants, stimulated 20th and 21st century research findings and philosophies. The legacy of Darwin's work permeates research on plant movement. For example, Darwin's demonstration that coleoptiles and roots fail to bend in response to light or gravity if their tips are removed helped researchers work toward the discovery of auxin and other plant hormones. Darwin's methodical observations on vine twining directions and circumnutation foreshadowed the recent discovery that 92% of vines twine in right‐handed helices, regardless of their location on the planet. Finally, Darwin's observation of the similarity between plant responses to stimuli and the responses of lower animals foreshadowed the current debate over whether plants have ‘behaviour’. Thus, even Darwin's lesser‐known works continue to influence research in the present day. © 2009 The Linnean Society of London, Botanical Journal of the Linnean Society, 2009, 160 , 111–118.     

Regional-Scale Assessment of Deer Impacts on Vegetation Within Western Connecticut,USA

Abstract: High densities of white-tailed deer (Odocoileus virginianus) are believed to cause broad-scale forest regeneration failure and loss of plant diversity. But, the empirical basis for such presumptions is limited. We, therefore, conducted a survey in western Connecticut, USA, woodlots to examine how spatial variation in deer densities influences variation in impacts on plant species abundance, identity and diversity, and tree regeneration. We also used a Geographic Information System to quantify trends between land-cover type and deer density. Deer density was not correlated with any vegetation or land use variable. This suggests that deer density is not a leading factor determining variation in vegetation impacts across western Connecticut.