Assortative mating in soldier beetles (Cantharidae: Chaulignathus ): test of the mate-choice hypothesis

Soldier beetles of 2 species, Chauliognathus basalis and C. deceptus , were examined to test the Crespi hypothesis that positive assortative mating by size is caused by mate choices. Specifically, we tested the prediction that if mate choice involves choosing the largest mate available, then mating individuals will be larger than nonmating individuals. Four samples were taken, at different times during the mating season, from each of 2 sites. Each sample consisted of mating pairs, nonmanting males, and nonmating females. Some of the samples contained beetles of both species; others contained beetles of a single species. For each gender elytron lengths of mating individuals were compared with elytron lengths of nonmating individuals. We found no effect of mating status (mating vs. nonmating) on elytron lengths in samples that exhibited assertive mating (which occurs where 2 species coexist). Surprisingly, we found a consistent effect of mating status on elytron lengths in samples that did not exhibit assortative mating (which occurs where only 1 species exists). Our results do not support the mate-choice hypothesis. Instead, mate choice and assortative mating appear to be alternative mating patterns in which mate choice occurs where a single species exists and assortative mating occurs where 2 species coexist.     

An overview of Hexabathynella (Crustacea,Syncarida, Parabathynellidae) with the description of a new species

A new species of the cosmopolitan genus Hexabathynella is described from Spain. This new species has four setae on the expopod of the uropod, the rest of the species in the genus have between one and three. The endopod of the uropod has two smooth setae of similar length and one plumose seta, these characters only appear in the new species within the genus. The antennal organ in the males is shown to be a new unique character for the genus. It is the third species of this genus that has been found in Spain. To date the genus consists of 18 species in the world. A key for identification of the 18 species of Hexabathynella is provided. It is the only cosmopolitan genus of Bathynellacea and it is distributed in Europe (nine species), Africa (one species), South America (two species), North America (three species) and Australia and New Zealand (three species).     

Zoogeography and evolutionary ecology of the genus Platorchestia (Crustacea,Amphipoda, Talitridae)

ABSTRACT

Species of the genus Platorchestia occur both in the northern hemisphere (18 species) and southern hemisphere (three species plus a synanthropically introduced species in South America and South Africa). The greater number of endemic Platorchestia species in the North Pacific Ocean suggests that it could be the epicentre of evolution for this genus. North-western Pacific Platorchestia includes 15 species which occupy five ecotopes: wrack (seven species), terrestrial leaf litter (five species), freshwater (one species), marsh (one species) and tentatively present in caves (one species). North-eastern Pacific Platorchestia includes only one putative driftwood specialist, with no other species found in North American coastal habitats. This compares with three good endemic Platorchestia species (plus two putative additional species) and only two ecotopes: wrack (three species) and freshwater (two species) from the North Atlantic Ocean, inclusive of the Gulf of Mexico and Mediterranean Sea. Insufficient data is available to consider Platorchestia zoogeography for the Arabian Sea and Bay of Bengal. Synanthropic dispersal involving Platorchestia in Polynesian outrigger canoes, or in solid ballast carried in the holds of wooden sailing ships has been identified as a potential complicating factor in the zoogeography of this genus. Platorchestia is proposed to have arisen on Laurasia and is therefore basically a northern hemisphere genus. Questions concerning Platorchestia zoogeography and evolutionary ecology are posed and two methods (more intensive field sampling and molecular genetics) are suggested to be the way to solve them.     

Expulsion and consumption of male ejaculates by promiscous female Euxesta eluta and Euxesta mazorca (Diptera: Ulidiidae)

While expulsion of male ejaculates by the females after copulation has been reported for various animal groups, expulsion followed by consumption of the expelled ejaculate is a rare behaviour outside spermatophylax-producing orthopterans. Among Diptera, this behaviour has been reported for a few species of Piophilidae, Empididae and Ulidiidae. Here we report on its occurrence among Euxesta eluta and Euxesta mazorca (Diptera: Ulidiidae). We also attempt to characterize the mating system of E. eluta in order to facilitate future hypothesis testing to understand the behavioural factors leading to the evolution of this peculiar behaviour. For this, courtship sequences, copulation duration, frequency of ejaculate expulsion and subsequent consumption, and latency to ejaculate expulsion for both E. eluta and E. mazorca were recorded. The time of sexual maturation, the time window of sexual receptivity during the day, and the mating frequency and variance in mating success for males and females (degree of polygamy) were determined for E. eluta. Both E. eluta and E. mazorca males engaged in elaborate courtship sequences involving visual and tactile displays before copulation. Females of both species almost invariably expelled and consumed ejaculates after copulation. Female E. eluta, required a 6- to 9-day period feeding on protein and sugar before becoming sexually receptive. Reproductive activity occurred continuously over the day with an early morning and late afternoon peak. Both males and females could mate multiply, with multiple partners over a 2-h observational period. Sexual network analysis revealed that some males and females had greater mating success than others. Ejaculate consumption appears to be widespread in the genus Euxesta. It is possible that females obtain nutrients from this behaviour while exerting some control over egg fertilization.     

Taxonomy of Sphaeromeria, Artemisia , and Tanacetum (Compositae, Anthemideae) based on randomly amplified polymorphic DNA (RAPD)

Relationships within, between, and among the Anthemideae genera Sphaeromeria, Artemisia , and Tanacetum were investigated using 238 randomly amplified polymorphic DNA (RAPD) markers obtained from twenty 10-mer primers amplified on genomic DNA. Forty-one populations from 16 taxa (15 species) were studied. Jaccard's coefficient of similarity and UPGMA clustering analysis were used to construct phenograms. T tests were used to make comparisons between samples at various systematic levels. DNA markers were 75% similar for conspecific populations. Sixteen Sphaeromeria populations (5 species) showed an average interspecific similarity of 21%. Interspecific similarity among 23 Artemisia populations (8 species with 2 subspecies of A. tridentata included) averaged 27%. Two Tanacetum species (1 population each) were 89% similar. The high similarity of Tanacetum species was in the range of observed values for conspecific populations; indeed those 2 species ( T. vulgare and T. boreale ) have been considered conspecific by some authors. The 3 subgenera of Artemisia studied ( Artemisia, Dracunculus , and Tridentatae ) formed separate groups. In comparison among the genera, Sphaeromeria was 18% similar to Artemisia (more similar to subgenus Tridentatae than the other Artemisia subgenera); intergeneric comparisons of Sphaeromeria and Artemisia and Tanacetum , which supports previously established morphological distinctions. Sphaeromeria potentilloides may be misplaced in the genus Sphaeromeria based on DNA marker results. It is likely that North American Anthemideae are circumboreal derivatives of ancestral Eurasian stock and that Sphaeromeria is derived from an Artemisia -like ancestor.     

Marine biodiversity on the Algerian Continental Shelf (Mediterranean Sea)

The Mediterranean Sea is known as a biodiversity hot spot, with 16,848 species reported. Biodiversity is higher in coastal areas and decreases with depth. However, knowledge about the southwestern sector remains scarce. For the last three decades, sampling of soft-bottom communities along the 1180 km of the shallow Algerian coast (0–136 m) has recorded 1642 macrobenthic species. There is a decreasing west–east species-richness gradient, especially for the total species richness and the amphipods. In addition, quantitative sampling in Bou Ismail Bay in summer 1988 (98 sampling sites for a total of 841 species) shows that diversity indices (i.e. species richness, >100 species for 0.2 m^?2; Shannon diversity, >6.0; and ES₅₀, >34) are among the highest for similar sand and muddy-fine sand communities in the Mediterranean Sea and the northeastern Atlantic Ocean. Bou Ismail Bay appears to have the highest species richness among Algerian bays, probably because of its variety of benthic habitats and the absence of significant pollution in this area. Monitoring must be undertaken to survey this high biodiversity, and a national strategy should be proposed to preserve high diversity zones.     

On a new species of centipede (Chilopoda,Geophilomorpha) from the Isles of Scilly

Several specimens of a small geophilomorph centipede were collected by the author from the Isles of Scilly between 1984 and 1987. The last legs bear a tuberculate pretarsus which is a diagnostic character of the North American genus Arenophilus but this species is not among those listed in Crabill's (1969) review of that genus.     

Mysidacés (Crustacea) de Kerguelen,Crozet et Bouvet (Océan Austral) récoltés par la Japonaise,le Marion-Dufresne (1972–82) et dans des contenus stomacaux d'oiseaux

This study deals with the Mysidacea (Crustacea) collected during the cruises organized by T.A.A.F. (Terres Australes et Antarctiques Françaises), between 1972 and 1982, in the subantarctic part of the Southern Ocean, off Bouvet, Marion, Prince Edward, Crozet, Kerguelen and Heard Islands. In spite of the large numbers of samples taken between the littoral and 2000 m, with various bottom sampling gears, only 8 species were caught. At the Kerguelen islands, the genus Mysidetes, with 2 species including M. morbihanensis n. sp., was the main constituent of the benthic littoral mysidacean fauna, while Boreomysis inermis was the main bathyal species. The analysis of stomach contents of birds indicates that some bathypelagic mysidacean species ascend to the surface layer.     

Mating behaviour,territoriality and natural history notes of Phyllomedusa ayeaye Lutz, 1966 (Hylidae: Phyllomedusinae) in south-eastern Brazil

The mating (male courtship, amplexus and oviposition) and male territorial behaviours of Phyllomedusa ayeaye are described from a high-altitude site in the state of Minas Gerais, south-eastern Brazil. Information related to male breeding success and territoriality, as well as egg clutch parameters, is provided, together with qualitative information regarding tadpole phenology and juvenile recruitment. In addition, estimations of sexual dimorphism and numbers of marked individuals are available through capture-mark-recapture sampling. Females bred with males within spatially clustered oviposition sites (broadleaf plants). In some cases, the amplectant couple actively searched for the oviposition site. Males defended territories from other males, employing both acoustic and physical interactions. Some males successfully maintained their calling sites over successive nights, and others seemed to switch among nearby sites during successive nights and tried to disrupt ongoing ovipositions. No significant relationship was found between physical attributes (snout vent length or body mass) of males with breeding success. Also, no influence of the number of nights a male was active in chorus and its breeding success was detected. Therefore, it is proposed that the mating system in P. ayeaye may be opportunistic. Additional information related to reproduction (egg clutch parameters and breeding behaviours) is also discussed for other species of the Phyllomedusa hypochondrialis group and compared with the results of the present study.     

Descriptions of two new species of the genus Agathis Latreille (Hymenoptera,Braconidae, Agathidinae) from Spain,with a record of mating by one species on flowers

Two new species of the genus Agathis Latreille, A. icarus sp. n. and A. nixoni sp. n., are described from southern Spain. Both species were observed feeding on the nectar of Anacyclus clavatus (Desf.) Pers.. (Asteraceae). A. nixoni was also observed mating on flowers. Mating by parasitoids at feeding sites is discussed.     

Discovery of the freshwater genus Sicyopus (Teleostei: Gobioidei: Sicydiinae) in Madagascar,with a description of a new species and comments on regional dispersal

In the Indo-Pacific area, insular rivers are mainly colonized by gobiids of the Sicydiinae subfamily. These species spawn in freshwater, where the free embryos drift downstream to the sea before returning to rivers to reproduce; they are amphidromous. These gobies are the greatest contributors to the fish diversity and have the highest levels of endemism. Among the nine known genera of Sicydiinae, only two have been found in the West Indian Ocean, and only one (Sicyopterus) is known from Madagascar. Recently, two surveys discovered a new species in the genus Sicyopus. Sicyopus lord sp. nov. differs from other species by a combination of characters that includes a particular colour pattern, similar in both sexes; more scales than its congeners in lateral series (35–43), transverse back series (12–18) and a shorter caudal fin length in male fish. This paper describes the new species and discusses the presence of this genus in Madagascar.     

Water mites from spring- and ground-water habitats in the Sultanate of Oman

Eight species of water mite were collected in 1996 during a biological survey with various sampling techniques by J. H. Stock, J. J. Vermeulen (both Amsterdam) and Abdul M. Al Nofli (Oman) from ground-water habitats of the Sultanate of Oman (Arabian peninsula). All species are recorded for the first time from the Arabian peninsula. Four species, representing the genera Monatractides, Bharatohydracarus (two species), and a genus and subfamily new to science, are described for the first time. The systematic and zoogeographical significance of these new records is discussed.     

Chromosome races in Sarcobatus (Sarcobataceae, Caryophyllales)

Sarcobatus Nees., a genus of North American halophytic shrubs, consists of 2 species: S. vermiculatus (Hook.) Torr. ( n = 18, 36), which is widespread in North America, and S. baileyi Cov ( n = 54), endemic to Nevada. Within S. vermiculatus , populations of n = 36 are widely distributed, whereas populations of n = 18 are found only in the Sonoran Desert, northern California, and northwestern Great Plains, locations at the periphery of the species range. Although the chromosome number of n = 18 is apparently a tetraploid, failure to form and n = 27 race intermediate to those of n = 18 and n = 36 suggests than n = 18 S. vermiculatus is of significant age and that it behaves chromosomally as a diploid. Sacrobatus has a long fossil pollen record and endured Pleistocene climatic extremes with little range displacement.     

On some African and Oriental Wolf Spiders (Araneae,Lycosidae): redescription of Pardosa oncka Lawrence from Africa,with notes on its generic position

Pardosa oncka Lawrence (with P. irrasa Roewer, P. kisokwea Roewer, P. resoluta Roewer, P. versuta Roewer and P. wittei Roewer here placed as junior synonyms) is described and illustrated. The male is recognized by its bifurcate embolus. The female has conspicuous mating plugs more or less concealing two pits in the epigyne. The species is widely distributed in Central and South Africa, and may be grouped in a separate genus (here not formally recognized) together with P. venatrix auctt. and some other species listed.     

Maintenance of colour polymorphism in the leaf beetle Chrysophtharta agricola (Chapuis) (Coleoptera: Chrysomelidae: Paropsini)

Intra-specific colour differences in insects may occur as a result of environmental factors such as food type, temperature and humidity, or may be under genetic control. These colour polymorphisms may result in fitness differences through several mechanisms, including mate selection, camouflage from or warning to natural enemies, and heat absorption. Two colour morphs of adult Chrysophtharta agricola (Chapuis) (Coleoptera: Chrysomelidae: Paropsini) are present in the field in mainland Australia and Tasmania: a common green-brown form, and a rare black form. Tasmanian populations were sampled to assess the frequency of each morph at eight localities. The black form represented less than 3% of beetles (N=1724), with the proportion not significantly different between localities. Crossing tests using the two colour morphs of C. agricola showed that the black form was genetically dominant over the common form. To assess whether colour morphs had any fitness differences, we measured pre-oviposition period, fecundity, longevity, adult size and egg hatch rate, which each showed no significant difference between colour morphs. Field sampling of mating pairs and rearing the offspring of field-collected females showed no evidence of non-random mating. Modelling the population over 100 generations confirmed that for this species, melanism is controlled by a dominant but neutral allele, and, thus, is maintained at a constant low level in the population.     

On some maerid and melitid material (Crustacea: Amphipoda) collected by the Hourglass Cruises (Florida). Part 2: Genera Dulichiella and Elasmopus,with a key to world Elasmopus

This paper deals with some of the Amphipoda Maeridae and Melitidae, i.e. one species in the genus Dulichiella and two in Elasmopus, collected during the Hourglass cruises, a 28-month sampling programme at 10 stations (5–73 m depth) on the central West Florida shelf. A key to world Elasmopus species is provided.     

A new genus with three new species of copepods from the family Diaixidae (Crustacea: Calanoida), and a redefinition of the family

Plankton samples taken in the Gulf of Carpentaria, Australia, yielded material of a new genus containing 3 new species: Anawekia spinosa gen. nov. et sp. nov., A. robusta sp. nov. and A. bilobata sp. nov., which are described herein. The family Diaixidae now contains 12 described species in 2 genera, 9 being in the genus Diaixis. It is noted that 3 of the Diaixis species (including the type species) share some features which are not shared with the remaining 6 species, and that these latter species should probably be placed into a third genus. An amplified redefinition of the family is given.     

Foraging behaviour of three sphaerodactylin geckos on Trinidad and Tobago (Sauria: Gekkonomorpha: Sphaerodactylini: Gonatodes)

Taxonomic families of insectivorous lizards are usually characterized by one of two distinct foraging modes, namely ambush ‘sit-and-wait’ or active ‘widely foraging’. In the Gekkonomorpha the situation has been unclear and in dispute, and among these, that in the Sphaerodactylini is almost unreported. We, therefore, examined the foraging mode of three sphaerodactylin species on Trinidad and Tobago, in May—June 2000 (totalling 72 individuals, observations averaging 23.6 min/individual). In terms of species averages, Gonatodes vittatus, G. humeralis and G. ocellatus all moved for only 1.6–3.55% of observation time (PTM, percent time moving), and switched from sitting to locomoting only 0.18–0.36 times per minute (MPM, moves per minute). The genus thus is a strict sit-and-wait forager. In G. vittatus, the foraging mode was unaffected by sex or habitat structure. In all three species, foraging mode was unaffected by the time of day or air temperature. In G. humeralis, foraging activity (PTM or MPM) correlated with light intensity in the forest within a population (at least MPM) and among populations (at least PTM). Among the three species, too, foraging activity (PTM and MPM) ranked with light intensity during sampling. In all three species, the geckos perched for 68–76% of the time (at any height) with the head pointing down, apparently so as to see better. In conclusion, the three species are strict sit-and-wait' visual hunters that are dependent on light.     

A new species in the genus Grandidierella Coutière (Crustacea: Amphipoda) from an Australian solar salt-works

Grandidierella propodentata sp. nov., a third Australian species of the genus, is described. It was collected from among algae in a hypersaline lagoon in Queensland. Sexual dimorphism of the uropods is reported for the first time in this genus.     

Australian thrips of the Haplothrips lineage (Insecta: Thysanoptera)

Keys are presented to the 11 genera and 50 species, including 21 new species, of Thysanoptera in Australia that are related to the worldwide genus Haplothrips Amyot and Serville. These taxa belong to what, in recent literature, has been called the “Haplothrips‐lineage”, that is, one of the three major radiations among the 2700 species and 350 genera of Thysanoptera Phlaeothripinae. The group is redefined, and the available tribal name Haplothripini shown to be appropriate. The character states on which the definition is based are discussed, and a list given of the 34 genera worldwide that can be included. The Australian species in these genera exhibit a diversity of biologies. Three genera involve species that invade galls induced by other thrips: Androthrips monsterae (Moulton) from New Guinea is newly recorded from Australia; Mesothrips jordani Zimmermann from South‐East Asia is newly recorded from Australia, with two new synonyms; the Asia‐Pacific genus, Euoplothrips Hood, includes two species in northern Australia. Three haplothripine genera are associated with grasses: one widespread genus, Apterygothrips Priesner, considered polyphyletic, includes only one Australian species; the only known species of Dyothrips Kudo is Oriental but extends into tropical Australia; Podothrips Hood, a circum‐tropical genus of thrips predatory on grass‐living coccoids, has 11 Australian species, six newly described. One grass‐associated genus, Bamboosiella Ananthakrishnan, is excluded from the Haplothripini. An Oriental genus of leaf‐ and flower‐living species, Dolichothrips Karny, includes one species in northern Australia, D. reuteri (Karny); Membrothrips Bhatti in which this species has been placed is considered a synonym. Karnyothrips Watson includes two species introduced to Australia, both predators of coccoids. Priesneria Bagnall includes three species from Australia, of which one fungus‐feeding species is newly described. Xylaplothrips Priesner is a widespread but ill‐defined, polyphyletic genus that currently includes three little‐known Australian species. Haplothrips is the main focus of this study, and character state variation among the Australian species is discussed. In total 24 species of Haplothrips from Australia are recognised, 14 being new species. Also included are the following, one new generic synonym, four new species synonyms, and one new combination. The 250 species worldwide in the genus are usually associated with the flowers of Asteraceae and Poaceae. In Australia, several of the species are specific to flowers, particularly of Poaceae and Cyperaceae but not Asteraceae. Almost half of these Australian species are presumed to be predatory on other small arthropods, and two have unusual host associations—with salt marsh Chenopodiaceae, and with the sori of Dicksonia tree ferns.