Revision of Microlaimidae, Erection of Molgolaimidae fam.n., and Remarks on the Systematic Position of Paramicrolaimus (Nematoda, Desmodorida)

The family Microlaimidae contains Bolbolaiminae subfam.n. (Bolbolaimus syn. Pseudomicro-laimus) and Microlaiminae ( Calomicrolaimus, Ixonema and Microlaimus ). The new family Molgolaimidae contains Aponematinae subfam.n. ( Aponema gen.n.) and Molgolaiminae subfam.n. ( Molgolaimus and Prodesmodora ). The main differentiating characters applied are: structures of the head region, shape of the oesophagus, position of the excretory pore, shape of the tail, structure of the gonads and ornamentation of the cuticle. The significance of porids and preanal supplements as distinguishing characters is, discussed. Microlaimidae are closely related to Desmodoridae; Molgolaimidae related to Spiriniidae. Paramicrolaimus is transferred from Microlaimidae to Spiriniidae.–Six species from the Øresund, Denmark, are redescribed: Microlaimus punctulatus Gerlach, 1950 and M. acinaces Warwick & Piatt, 1973; Aponema torosus (Lorenzen, 1973) gen.n., comb.n. (syn. Microlaimus torosus Loren-zen, 1973); Molgolaimus allgeni (Gerlach, 1950) comb.n. (syn. Microlaimus allgeni Gerlach, 1950) and M. turgofrons (Lorenzen, 1972) comb.n. (syn. Microlaimus turgofrons Lorenzen, 1972); Paramicrolaimus spirulifer Wieser, 1959.     

Associative learning of host presence in non‐host environments influences parasitoid foraging

1. Parasitoids are known to utilise learning of herbivore‐induced plant volatiles (HIPVs) when foraging for their herbivorous host. In natural situations these hosts share food plants with other, non‐suitable herbivores (non‐hosts). Simultaneous infestation of plants by hosts and non‐hosts has been found to result in induction of HIPVs that differ from host‐infested plants. Each non‐host herbivore may have different effects on HIPVs when sharing the food plant with hosts, and thus parasitoids may learn that plants with a specific non‐host herbivore also contain the host. 2. This study investigated the adaptive nature of learning by a foraging parasitoid that had acquired oviposition experience on a plant infested with both hosts and different non‐hosts in the laboratory and in semi‐field experiments. 3. In two‐choice preference tests, the parasitoid Cotesia glomerata shifted its preference towards HIPVs of a plant–host–non‐host complex previously associated with an oviposition experience. It could, indeed, learn that the presence of its host is associated with HIPVs induced by simultaneous feeding of its host Pieris brassicae and either the non‐host caterpillar Mamestra brassicae or the non‐host aphid Myzus persicae. However, the learned preference found in the laboratory did not translate into parasitisation preferences for hosts accompanying non‐host caterpillars or aphids in a semi‐field situation. 4. This paper discusses the importance of learning in parasitoid foraging, and debates why observed learned preferences for HIPVs in the laboratory may cancel out under some field experimental conditions.     

Interactive effects of herbivory and sand burial on growth of a tropical dune plant, Ipomoea pes-caprae

1. This study examined the effects of insect herbivory, sand burial, and the interactive effects of these factors, on the growth of beach morning glory, Ipomoea pes-caprae, a common tropical dune plant. Levels of herbivory and sand burial were manipulated on individual shoots, and effects on stem growth, leaf production, and production of adventitious roots and axillary branches by nodes were examined.
2. Sand burial had a significant positive effect on the production of roots, but did not affect growth in stem length or leaf production.
3. Effects of herbivory were consistently negative, and persisted for 6 weeks after the herbivore damage was incurred. Stem growth rates and leaf production decreased and the production of bare nodes (with no roots or branches) and mortality of apical meristems increased.
4. Interactive effects of herbivory and sand burial influenced both leaf production and root production. In the case of root production, the effects of herbivory in decreasing the proportion of nodes that produced roots occurred only in the presence of burial. In contrast, burial masked the negative effects of herbivory on leaf production.     

Proteomic and phenotypic profiling of the amphibian pathogen Batrachochytrium dendrobatidis shows that genotype is linked to virulence

Population genetics of the amphibian pathogen Batrachochytrium dendrobatidis ( Bd ) show that isolates are highly related and globally homogenous, data that are consistent with the recent epidemic spread of a previously endemic organism. Highly related isolates are predicted to be functionally similar due to low levels of heritable genetic diversity. To test this hypothesis, we took a global panel of Bd isolates and measured (i) the genetic relatedness among isolates, (ii) proteomic profiles of isolates, (iii) the susceptibility of isolates to the antifungal drug caspofungin, (iv) the variation among isolates in growth and phenotypic characteristics, and (v) the virulence of isolates against the European common toad Bufo bufo . Our results show (i) genotypic differentiation among isolates, (ii) proteomic differentiation among isolates, (iii) no significant differences in susceptibility to caspofungin, (iv) differentiation in growth and phenotypic/morphological characters, and (v) differential virulence in B. bufo . Specifically, our data show that Bd isolates can be profiled by their genotypic and proteomic characteristics, as well as by the size of their sporangia. Bd genotypic and phenotypic distance matrices are significantly correlated, showing that less-related isolates are more biologically unique. Mass spectrometry has identified a set of candidate genes associated with inter-isolate variation. Our data show that, despite its rapid global emergence, Bd isolates are not identical and differ in several important characters that are linked to virulence. We argue that future studies need to clarify the mechanism(s) and rate at which Bd is evolving, and the impact that such variation has on the host–pathogen dynamic.     

Isolation of active ribulose 1,5-bisphosphate carboxylase from glanded cotton (G. hirsutum)

Ribulose, 1,5-bisphosphate carboxylase has been isolated from leaves of glanded cotton, (Gossypium hirsutum L. cv. TM1), by techniques described. A yield exceeding 4.5 mg enzyme per gram leaf tissue has been obtained by utilizing a sodium homogenizing buffer without the addition of any reducing agent. Sodium dodecylsulfate gel electrophoresis of the enzyme shows the fraction to be relatively free of contaminants. Enzymic assays of the isolate give a specific activity of 1.1 μmol CO₂ fixed (min-mg protein)^?1 at 30°C.     

Pseudocatamachilis gen.n., a new genus of Machilidae (Insecta, Apterygota, Microcoryphia) from Spain

A new genus, Pseudocatamachilis gen.n. is established on the basis of a thorough study of many specimens male and female of Catamachilis torquata (Nav#aAs, 1905). All type material was lost during the Spanish civil war (1936-39). A neotype is designated and the species redescribed. Genus Pseudocatamachilis is related to Catamachilis Silvestri and Promesomachilis Silvestri, but distinguished from these genera by the type of ovipositor and the presence of two pairs of parameres, among other characteristics given in the text.     

Relationships between parasitoid host range and host defence: a comparative study of egg encapsulation in two related parasitoid species

Abstract. Parasitoid host range may proceed from traits affecting host suitability, traits affecting parasitoid foraging behaviour, or both. We tested the hypothesis that encapsulation can be used as a reliable indicator of parasitoid host range in two closely related larval endoparasitoids of Lepidoptera. Cotesia glomerata (L.) (Hymenoptera: Braconidae) is gregarious and a generalist on several species of Pieridae, whereas C. rubecula (Marshall) is solitary and specific to Pieris rapae (L.). We determined the effects of host species ( Pieris brassicae (L.), P. napi (L.) and P. rapae ) (Lepidoptera: Pieridae) and host developmental stage (early first, second and third instar) on encapsulation of parasitoid eggs. Host species and parasitoid species, as well as the resulting interaction between these two factors had significant effects on encapsulation of Cotesia eggs. Encapsulation in Pieris hosts was much lower for C. glomerata (<34%, except for second and third instar of P. rapae ) than for C. rubecula (>32%), even when the latter was parasitizing P. rapae. Encapsulation increased with the age of the larvae, although the only significant difference was for C. glomerata. Overall, P. rapae showed a stronger encapsulation reaction than P. brassicae and P. napi. Encapsulation levels of C. glomerata corresponded well to patterns of female host species and host age preference for oviposition and parasitoid larval performance. In contrast, percentages of encapsulation of C. rubecula were not consistent with host preference and host suitability. We argue that encapsulation alone is unlikely to provide a sufficient explanation for C. glomerata and C. rubecula host range.