The reproductive behavior of six species of Namib desert tenebrionid beetles (Coleoptera: Tenebrionidae)

The reproductive behavior of six species of tenebrionid beetles (Coleoptera: Tenebrionidae) was studied in the Namib Desert of southern Africa. In three species, males follow closely behind females (following behavior), while in the other three species, males mount females and remain clasped to them for extended periods (riding behavior). Following behavior occurs before and sometimes after copulation, while riding behavior occurs primarily after copulation. Males of all six species guard females from contesting males, although the effectiveness of guarding is greater in riding species. The evolution of the two male mating strategies does not appear to be related to operational sex ratio differences but, rather, to differential tendencies of females to remate. Variation in total pair duration within following and riding species may be attributed partly to species differences in operational sex ratio. However, pair durations are not affected by experimental manipulations of sex ratio in each species.     

Climatic correlates of body size in European tenebrionid beetles (Coleoptera: Tenebrionidae)

Tenebrionidae are one of the largest families of beetles and are known for their adaptations to hot and dry climates. An increase in body size also increases the volume/surface area ratio, which reduces transpiration, and hence water loss. If an increase in body size is an important adaptation in tenebrionids to cope with increasing aridity, we expect a correlation between body size and climatic gradients in the major tenebrionid clades. Alternatively, we can postulate that arid climates do not drive body size evolution, but rather select, from a wider fauna containing species of any size, those that have larger bodies. In this case we expect that drier regions will host faunas that contain, on average, larger species. To test the first hypothesis, we correlated inter-specific body size variation in the main tenebrionid clades with climatic gradients in Europe. We found only weak trends. To test the second hypothesis, we regressed mean body size of European country faunas against climatic characteristics. We found a strong increase in body size in southern faunas experiencing hot and dry climates. Therefore, increase in body size is not a major adaptation in tenebrionid evolution, but climate is an important filtering factor that determines a prevalence of larger species in southern Europe.     

A multidimensional characterization of rarity applied to the Aegean tenebrionid beetles (Coleoptera Tenebrionidae)

This paper attempts to use museum collection data to estimate measures of species rarity and then to relate these measures to extinction risk. For this purpose, 170 taxa (138 species and 32 subspecies) of tenebrionid beetles from 32 Aegean Islands (Greece) were considered. For each taxon, rarity was evaluated as geographic distribution (mean incidence on islands in the archipelago), potential habitat exploitation (total area of the islands occupied on the total area of the study system) and contactability (number of decades of taxon’s records on the total number of decades of assumed persistence from 1870 to 2000). All of these indices were correlated to each other. Whether expressed in terms of range size or habitat exploitation rarity was a major determinant of a species’ risk of extinction (evaluated as extinction decade). Thus, the designation of rarity provides a good basis for identifying species that are most in need of conservation at a particular scale.     

To the systematics and nomenclature of tenebrionid beetles of the tribes Phaleriini, Lachnogyini, Klewariini, and Blaptini (Coleoptera, Tenebrionidae)

The following new synonymies are established: Paranemia Heyden, 1892 = Taklamakania Ferrer et Yvinec, 2004, syn. n.; Paranemia schroederi Heyden, 1892 = P. argiropuloi A. Boga?ev, 1965 = P. argyropuloi A. Boga?ev, 1967, syn. n.; Paranemia bicolor Reitter, 1895 = Taklamakania lepetzi Ferrer et Yvinec, 2004, syn. n.; Lachnogya squamosa Ménétriés, 1849 = L. skopini Ferrer et Yvinec, 2004, syn. n. Placement of the genus Lachnodactylus Seidl. in the tribe Lachnogyini and the distinctness of the tribe Klewariini are substantiated. The larva of Agnaptoria anthracina G. Medv. is described.     

Mycorrhizal associations and reproductive isolation in three closely related Orchis species

Background and Aims

The maintenance of species boundaries in sympatric populations of closely related species requires some kind of reproductive isolation that limits gene flow among species and/or prevents the production of viable progeny. Because in orchids mycorrhizal fungi are needed for seed germination and subsequent seedling establishment, orchid–mycorrhizal associations may be involved in acting as a post-mating barrier.

Methods

We investigated the strength of post-mating barriers up to the seed germination stage acting between three closely related Orchis species (Orchis anthropophora, O. militaris and O. purpurea) and studied the role of mycorrhizal fungi in hybridization by burying seed packets of pure and hybrid seeds. After retrieval and assessment of seed germination, the fungi associating with protocorms originating from hybrid and pure seeds were determined and compared with those associating with adult individuals using DNA array technology.

Results

Whereas pre-zygotic post-mating barriers were rather weak in most crosses, post-zygotic post-mating barriers were stronger, particularly when O. purpurea was crossed with O. anthropophora. Germination trials in the field showed that seed germination percentages of hybrid seeds were in most cases lower than those originating from pure crosses. In all species pair combinations, total post-mating reproductive isolation was asymmetric. Protocorms associated with a smaller range of fungal symbionts than adult plants, but there was considerable overlap in mycorrhizal associations between protocorms and their respective parents.

Conclusions

Our results suggest that mycorrhizal associations contribute little to reproductive isolation. Pre-mating barriers are probably the main factors determining hybridization rates between the investigated species.     

Ecological differentiation and reproductive isolation of two closely related sympatric species of Oenanthe (Apiaceae)

Oenanthe conioides is a lower Elbe endemic plant species growing in the freshwater tidal zone around Hamburg (Germany). Its closest relative Oenanthe aquatica is widely distributed in Eurasia and grows in calm and shallow freshwater. The two species differ in habitat requirements but are otherwise sympatrically distributed, suggesting that ecological divergence has to be maintained in the face of gene flow. In the present study, we investigated ecological differentiation and reproductive isolation in these two species. An amplified fragment length polymorphism analysis found clear genetic differentiation between the two species implying reproductive isolation. A reciprocal transplantation experiment including artificial F₁ hybrids showed strong selection against immigrants. In the two parental habitats, the non‐native species are less fit than the native species. Hybrids are less fit in the habitat of Oe. aquatica but perform as well as the native species in the habitat of Oe. conioides. We hypothesize that selection against immigrants is the most important component of reproductive isolation between the two species, and that selection against immigrants is the result of exposure to cold and wind in the tidal habitat of Oe. conioides and to herbivory in the habitat of Oe. aquatica. These results are congruent with a role for differential ecological selection in the formation and maintenance of these two species. © 2010 The Linnean Society of London, Biological Journal of the Linnean Society, 2010, 101 , 526–535.     

Critical examination of postulated cladistic relationships among species of flour beetles (genus Tribolium,Tenebrionidae, Coleoptera)

Cytological considerations have led to the hypothesis that Tribolium confusum (CF) evolved from an ancestor similar to T. castaneum (CS) by translocation of an autosome to the X chromsome, and that T. destructor (DEST) was derived from CF. T. brevicornis (BREV) is regarded as the most primitive on morphological grounds. Electrophoretic analyses of 19 strains of CS, 7 of CF, and 1 each of DEST and BREV do not support this postulated evolutionary pathway. CF and CS are much more similar to BREV than they are to each other. (Comparisons of morphological mutations in CS and CF also indicate that the two species are not similar genetically.) DEST and CF are very dissimilar electrophoretically. It is likely that the species evolved independently from an ancestral stock which may be represented by BREV. Recognition of gene homology in different species is the keystone for all attempts at constructing genetically meaningful evolutionary pathways. The difficulties involved in doing so are pointed out.     

A new genus and species of darkling beetles of the tribe Helopini (Coleoptera,Tenebrionidae) from Turkey

A new genus and species Microdocnemis xerophilicus gen. et sp. n. of the tenebrionid-beetle tribe Helopini is described from southwestern Turkey. The new genus belongs to the cylindrinotoid group of genera and is closely related to the genus Odocnemis Allard, 1876 in the structure of the male genitalia and female genital tubes and in the denticulation of the inner margin of the fore tibia. Microdocnemis differs from Odocnemis in the following characters: body very weakly flattened dorsally and ventrally; apical part of elytra, body ventrally, and epipleura with hairs; anal sternite with double bordering; apical margins of tibiae with short thick spines. The only species of the new genus inhabits xerophytic stony biotopes and has been found under stones; the species of the genus Odocnemis live on tree trunks covered with lichens.     

The taxocene of lichen-feeding darkling beetles (Coleoptera,Tenebrionidae: Helopini) in a forest-steppe ecotone

The taxocene of lichen-feeding darkling beetles from the tribe Helopini is studied in the steppes of the south of Rostov Province. The species of lichens grazed on by the representatives of this tribe are identified for the first time and dependence of circadian activity and spatial distribution of adults on temperature and air humidity is shown. Global warming and human activities may have caused degradation of steppe lichen communities that formed the dietary base for the lichen-feeding darkling beetles in natural ecosystems. As a result, 3 out of 4 beetle species completely left steppe biotopes for tree shelterbelts. This caused a change in the trophic relationships (transition from epigeic to epiphytic lichens) and in the spatial distribution of darkling beetles, promoted the establishment of competitive interactions, and increased the duration of circadian and seasonal activity due to the lengthening of the periods with optimum temperature and air humidity for each species.     

Strong reproductive isolation between closely related tropical sea urchins (genus Echinometra)

Morphological, mitochondrial DNA, and single-copy nuclear DNA differences show that the tropical sea urchin Echinometra mathaei is composed of at least four independent gene pools. Evolutionary distance between species measured with restriction-site changes (for mitochondrial DNA) and thermal renaturation (for single-copy nuclear DNA) is 1%-3% nucleotide divergence. Thus these are the most closely related sea urchin species known. Despite this genetic similarity, strong blocks to interspecific fertilization exist in this genus. Between two Hawaiian species, few eggs are fertilized in hybrid crosses, even in the presence of excess sperm. Microscopic examination of such crosses shows that sperm attachment to heterologous eggs is inhibited. Measures of genetic distance between species can help reveal the tempo of speciation and allow comparisons of morphological, biochemical, and ecological characteristics to be made in an evolutionary framework. Our results show that strong reproductive isolation can evolve by changes in egg-sperm recognition without extensive genetic divergence between species. Such mechanisms are most easily studied in free-spawning animals such as sea urchins but as well may represent an important aspect of speciation in species with internal fertilization.     

Life forms and strategies of lichen-feeding darkling beetles (Coleoptera,Tenebrionidae: Helopini)

Trophic relations of lichen-feeding darkling beetles of the tribe Helopini in Turkey, the Caucasus, and Anti-Atlas are considered. This group is the most diverse in relict Anatolian forests of Cedrus libani, Abies cilicica, Pinus nigra, Juniperus spp., and Quercus cerris, where multitaxon lichenophagous assemblages exist. Three life strategies for attenuation of interspecific competition are distinguished: (1) differentiation of the consumed lichens, (2) separation of the life forms based on the types of the lichens consumed, and (3) segregation of circadian activity in adults. We assume that adaptation of the Helopini larvae to the soil life promoted their wide distribution in different landscapes by elimination of the limiting factor for completing their life cycles, namely the need for ligneous substrate of old rotting trees. The possibility of using lichen-feeding beetles of the tribe Helopini in ecosystem and lichen indication is considered.     

Multiple-chromosome sex systems in the darkling beetles Blaps gigas and Blaps gibba (Coleoptera, Tenebrionidae)

We have studied mitotic and meiotic chromosomes in the males of two species of Blaps: B. gigas and B. gibba. Karyological characteristics such as the occurrence of a multivalent configuration at diakinesis and two types of metaphase-II spreads support the notion that multiple-chromosome sex systems involving five chromosomes in B. gigas and eight chromosomes in B. gibba have developed in these species. Results obtained by means of silver staining and C-banding techniques suggest that the complex sex systems occurring in B. gigas and B. gibba may have originated from exchanges of terminal ribosomal genes among the Y chromosome and some autosomes.     

New data on the fauna of the tenebrionid beetle genus Agnaptoria Rtt. (Coleoptera, Tenebrionidae) of China

Eight new species of the genus Agnaptoria are described from the eastern part of the Tibet Highland: A. minuta sp. n., A. crassa sp. n., A. lauta sp. n. (Sichuan), A. kunda sp. n., A. proba sp. n. (Gansu), A. shangmengi sp. n., A. danbaensis sp. n. (Sichuan), and A. amdoensis sp. n. (Quinghai). A new material on A. shamaevi G. Medv., A. abdita G. Medv., and A. anthracina G. Medv. is reported with data on the variation of the anatomy of male genitalia and spermatheca in the latter species.     

Spatial structure of community of darkling beetles (Coleoptera: Tenebrionidae) in the Negev Highlands, Israel

The distribution of niches in resource space of darkling beetles of Negev desert, Israel were studied using discriminant analysis Seventeen environmental variables (substrate structure and vegetation) were measured at 375 plots within 15 grids The first three discriminant axes account for 77% of the variance and reflect a soil structure gradient from sand to clay (the first axis), a gradient of increasing productivity (the second axis), and a type of vegetation architecture (the third axis) Abundance and biomass of tenebrionids increased linearly along the first, the second and the third axes Species richness and diversity had a slanting parabola shape along the substrate axis and increased along the productivity axis There were two distinct spatial guilds of tenebrionid species One guild was composed by species that preferred sandy-gravel soils, and another guild consisted of species that preferred clay soils Niche overlapping of the sandy-gravel species was lower than that of the clay species Niches of the sandy-gravel species were randomly distributed in the resource space Those of the clay species formed a tight cluster with most niches placed in the center of the space, representing the centrifugal type of organization The conformity of the guild structure with the different types of organization was supported by compansons between empirical data and stochastic models The border between these two guilds matches with proposed earlier biogeographical boundary (Ramon-Zohar line)     

Cytogenetics of the darkling beetles Zophobas aff. confusus and Nyctobates gigas (Coleoptera, Tenebrionidae)

Males of Zophobas aff. confusus and Nyctobates gigas (Tenebrionidae) collected in the State of Pernambuco, Brazil, were studied through conventional staining, C-banding, silver nitrate impregnation (AgNO(3)), and the base specific fluorochromes CMA(3) and DAPI. Z. aff. confusus was found to have 2n = 20 (9+Xyp) while N. gigas exhibited 2n = 18 (8+neoXY). Large pericentromeric blocks of constitutive heterochromatin (CH) were detected throughout the autosomal complement of the two species, except in one autosomal pair of N. gigas in which no heterochromatic block was observed. The sex chromosomes of both species were almost totally heterochromatic. Double staining with CMA(3)/DA (distamycin) and DAPI/DA marked CH in Z. aff. confusus. However, DAPI staining was more intense. N. gigas was found to possess blocks of CH-positive CMA(3) and homogeneous DAPI. AgNO(3) staining also revealed differences between the two species. In Z. confusus an NOR was observed in the sexual bivalent Xyp and N. gigas was found to have an autosomal NOR.     

Evidence of reproductive isolation among closely related sympatric species of Serrasalmus (Ostariophysii, Characidae) from the Upper Madeira River, Amazon, Bolivia

The delimitation of the Serrasalmus species (Characiformes, Serrasalminae) from the Bolivian Amazon (Amazonas, Madeira) was examined using intron length polymorphism assessed by EPIC-PCR. The six pairs of primers provided 16 polymorphic loci across the species of the region and the allelic diversity ranged between two and 10 alleles per locus. For each locus, the lack of departure from Hardy-Weinberg expectations in a large number of the populations analysed and the homogenous distribution of linkage disequilibrium between paralogous loci and loci belonging to different intronic systems provided strong lines of evidence that the 16 amplified loci constituted independent neutral markers. Furthermore, allelic diversity was size-dependent, thereby indicating that insertion-deletions occurred frequently but randomly in introns, and that intron length polymorphism was a valid marker for investigating the systematics of piranhas. EPIC-PCR demonstrated that eight of the nine nominal species of piranha of the Upper Madeira were reproductively isolated and identified a new species that differed from its closest morphological and genetic relatives by seven diagnostic or semi-diagnostic loci. By contrast, no diagnostic or semi-diagnostic locus was found between S. spilopleura and S. eigenmanni , nor were their allelic frequencies different, thereby questioning the validity of their biological species status, at least in the Upper Madeira. This study, which was one of the first applications of EPIC-PCR to a large-scale molecular systematic purpose, demonstrates that it is a rapid, reliable and cost-effective tool for elucidating issues pertaining to fish systematics.     

Susceptibility of last instar red flour beetles and confused flour beetles (Coleoptera: Tenebrionidae) to hydroprene.

Last instar larvae of the red flour beetle, Tribolium castaneum (Herbst), and the confused flour beetle, Tribolium confusum Jacquelin du Val, were either exposed for 8-144 h on concrete treated with 1.9 x 10(-3) mg(AI)/per cm2 hydroprene, or continually exposed on concrete treated with 9.8 x 10(-4) to 1.9 x 10(-3) mg[AI]/per cm2 hydroprene. In both tests, larvae were exposed and held at 27 or 32 degrees C and 40, 57, or 75% RH. When larvae were exposed with no food to hydroprene for different time intervals, then transferred to untreated concrete containing flour, consistent effects were produced only at 144 h. At this exposure interval, the percentage of beetles arrested in the larval stage after 3-4 wk was generally greater at 75% RH compared with 40 and 57% RH, but there were no differences between species or temperature. The percentages of dead adult red flour beetles and live adults with morphological deformities were also greatest at 75% RH, and defects were more prevalent in red flour beetles than in confused flour beetles. When larvae were continually exposed to different concentrations of hydroprene on concrete that contained flour, the percentage of arrested larvae, dead adults, and live adults of both species generally increased with concentration. There were more deleterious effects at 75% RH compared with either 40 or 57% RH, and effects were more pronounced in the red flour beetle compared with the confused flour beetle. In both experiments, temperature effects were variable and inconclusive. Results indicate that continual exposure of last instar red flour beetle and confused flour beetle to hydroprene can limit population development, but exposure intervals of >6 d may be required for maximum effectiveness.