Host specificity of ambrosia and bark beetles (Col., Curculionidae: Scolytinae and Platypodinae) in a New Guinea rainforest

Abstract.  1. Bark and ambrosia beetles are crucial for woody biomass decomposition in tropical forests worldwide. Despite that, quantitative data on their host specificity are scarce.
2. Bark and ambrosia beetles (Scolytinae and Platypodinae) were reared from 13 species of tropical trees representing 11 families from all major lineages of dicotyledonous plants. Standardised samples of beetle-infested twigs, branches, trunks, and roots were taken from three individuals of each tree species growing in a lowland tropical rainforest in Papua New Guinea.
3. A total of 81 742 beetles from 74 species were reared, 67 of them identified. Local species richness of bark and ambrosia beetles was estimated at 80–92 species.
4. Ambrosia beetles were broad generalists as 95% of species did not show any preference for a particular host species or clade. Similarity of ambrosia beetle communities from different tree species was not correlated with phylogenetic distances between tree species. Similarity of ambrosia beetle communities from individual conspecific trees was not higher than that from heterospecific trees and different parts of the trees hosted similar ambrosia beetle communities, as only a few species preferred particular tree parts.
5. In contrast, phloeophagous bark beetles showed strict specificity to host plant genus or family. However, this guild was poor in species (12 species) and restricted to only three plant families (Moraceae, Myristicaceae, Sapindaceae).
6. Local diversity of both bark and ambrosia beetles is not driven by the local diversity of trees in tropical forests, since ambrosia beetles display no host specificity and bark beetles are species poor and restricted to a few plant families.     

Epistylis helicostylum n. sp., a New Peritrichous Ciliate with an Allometric Stalk Formation

SYNOPSIS. A new peritrichous ciliate, Epistylis helicostylum n. sp. is described. It lives attached to the extremities of the ostracod Eucypris virens as its specific symphoriont. A spiral structure forming a protective theca for the colony of daughter animals is produced by the allometric growth of the outer sheath of the stalk. The whole process of its formation is described.     

Cloning and Characterization of New Repetitive Sequences in Field Bean (Vicia fabaL.)

Five new repetitive sequences have been isolated from theViciafabagenome, by cloning bands visible on agarose gel electrophoresisafter digestion of genomic DNA with various restriction enzymes.The sequences were 109 to 584 bp long, their abundance rangingfrom 5x10⁴to 5x10⁵copies per haploid genome. Southern blot andinsituhybridization revealed that four of five newly isolatedrepeats were dispersed in theV. fabagenome. One of the repeats(TIII15) showed tandem organization with several major hybridizationspots on mitotic chromosomesin situ.These sites were distributedin euchromatic as well as in heterochromatic chromosomal regions,and in several loci they were simultaneously localized withpreviously describedFokI repeated elements. The sequence ofTIII15 comprises four 26–27 bp subrepeats, but sharesno homology toFokI elements which have similar sequence organization.All newly described sequences were highly specific forV. faba,withlittle or no hybridization to DNA of otherViciaspecies, andno hybridization to DNA of other legumes tested.Copyright 1999Annals of Botany Company Vicia faba, field bean, repeated DNA sequences, FISH, PRINS, genome organization, copy number.     

Brooklynella hostilis n. g., n. sp., a Pathogenic Cyrtophorine Ciliate in Marine Fishes*

SYNOPSIS. Brooklynella hostilis is a new genus and new species of highly lethal Chilodonella-like parasite in the gills of marine fishes. It differs from other dysteriid ciliates by a combination of these features: 1) posterior-ventral adhesive apparatus consisting of a single glandular organelle that lacks a distinct discharging canal or podite; 2) the kinetosomes cover the entire ventral surface, except the left posterior portion of the body; the outer right kinety is divided into 2 segments; the middle postoral kinetyues as a row of kinetosomes without cilia around the glandular organelle; 3) there are never more than 9 nematodesmata; and 4), there are numerous small micronuclei. The lesions caused by the infection vary from a mild inflammatory reaction to extreme tissue damage resulting in severe hemorrhages, desquamation, and fusion of the gill lamellae.     

Observations on the Ultrastructure of the Buccal Apparatus in Thigmotrich Ciliates and their Bearing on Thigmotrich-Peritrich Affinities*

SYNOPSIS. In the first use of electron microscopy in a comparative investigation of ciliates belonging to the order Thigmotrichida, ultrastructural data were collected on ciliary organelles of the buccal area. Species studied included members of the genera Ancistrum and Boveria. Analysis of the findings suggest close affinities between thigmotrich and peritrich ciliates. Further comparison with studies on hymenostome (sensu lato) ciliates supportes the hypothesis of a common ancestral stock in the phylogenetic history of all 3 of these groups. Structures very likely homologous in species of hymenostomes, thigmotrichs, and peritrichs include: the undulating membrane, the polykineties, the oral ribs, the filamentous reticulum, and a small field of barren kinetosomes.