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Water Beetles (water + beetle)
Selected AbstractsEffects of seasonal variation in salinity on a population of Enochrus bicolor Fabricius 1792 (Coleoptera: Hydrophilidae) and implications for other beetles of conservation interestAQUATIC CONSERVATION: MARINE AND FRESHWATER ECOSYSTEMS, Issue 1 2003M.T. Greenwood Abstract 1.A population of Enochrus bicolor (Fabricius) was monitored over a 4-year period (March 1997,March 2001) from a coastal brackish pool in S.E. Essex. This water beetle, together with Ochthebius marinus (Payk.), O. viridis Peyrhiff, O. punctatus Steph., Hygrotus parallelogrammus (Ahrens), Berosus affinis Brulle, Agabus conspersus, (Marsham), Rhantus frontalis (Marsham), R. suturalis (MacLeay), Paracymus aeneus (Germar), and Haliplus apicalis Thompson, are all taxa of conservation interest. 2.Enochrus bicolor was present in most months, with greatest adult abundances being recorded in August and September each year. 3.During the study period salinity values ranged from 4.7 ppt (parts per thousand) to 62.6 ppt. 4.Correlation analysis and the development of regression models indicated that the highest abundances of E. bicolor coincided with maximum water temperature in the late summer,early autumn. However, when the natural seasonal signal was removed by standardizing the series, a relatively weak association with the relative abundance of E. bicolor and conductivity was observed. 5.The conservation of E. bicolor and other organisms associated with brackish water habitats subject to irregular marine inundation is considered. Copyright © 2002 John Wiley & Sons, Ltd. [source] Does habitat use explain large scale species richness patterns of aquatic beetles in Europe?ECOGRAPHY, Issue 2 2003Ignacio Ribera Regularities in species richness are widely observed but controversy continues over its mechanistic explanation. Because richness patterns are usually a compound measure derived from taxonomically diverse species with different ecological requirements, these analyses may confound diverse causes of species numbers. Here we investigate species richness in the aquatic beetle fauna of Europe, separating major taxonomic groups and two major ecological types, species occurring in standing and running water bodies. We collated species distributions for 800+ species of water beetles in 15 regions across western Europe. Species number in any of these regions was related to three variables: total area size, geographic connectedness of the area, and latitude. Pooled species numbers were accurately predicted, but correlations were different for species associated with either running or standing water. The former were mostly correlated with latitude, while the latter were only correlated with the measure of connectedness or with area size. These differences were generally also observed in each of the four phylogenetically independent lineages of aquatic Coleoptera when analysed separately. We propose that effects of habitat, in this case possibly mediated by different long term persistence of running and standing water bodies, impose constraints at the population or local level which, if effective over larger temporal and spatial scales, determine global patterns of species richness. [source] A ,polarisation sun-dial' dictates the optimal time of day for dispersal by flying aquatic insectsFRESHWATER BIOLOGY, Issue 7 2006ZOLTÁN CSABAI Summary 1. Daily changes in the flight activity of aquatic insects have been investigated in only a few water beetles and bugs. The diel flight periodicity of aquatic insects and the environmental factors governing it are poorly understood. 2. We found that primary aquatic insects belonging to 99 taxa (78 Coleoptera, 21 Heteroptera) fly predominantly in mid-morning, and/or around noon and/or at nightfall. There appears to be at least four different types of diurnal flight activity rhythm in aquatic insects, characterised by peak(s): (i) in mid-morning; (ii) in the evening; (iii) both in mid-morning and the evening; (iv) around noon and again in the evening. These activity maxima are quite general and cannot be explained exclusively by daily fluctuations of air temperature, humidity, wind speed and risks of predation, which are all somewhat stochastic. 3. We found experimental evidence that the proportion (%) P(,) of reflecting surfaces detectable polarotactically as ,water' is always maximal at the lowest (dawn and dusk) and highest (noon) angles of solar elevation (,) for dark reflectors while P(,) is maximal at dawn and dusk (low solar elevations) for bright reflectors under clear or partly cloudy skies. 4. From the temporal coincidence between peaks in the diel flight activity of primary aquatic insects and the polarotactic detectability P(,) of water surfaces we conclude that the optimal times of day for aquatic insects to disperse are the periods of low and high solar elevations ,. The , -dependent reflection,polarisation patterns, combined with an appropriate air temperature, clearly explain why polarotactic aquatic insects disperse to new habitats in mid-morning, and/or around noon and/or at dusk. We call this phenomenon the ,polarisation sun-dial' of dispersing aquatic insects. [source] Parallel habitat-driven differences in the phylogeographical structure of two independent lineages of Mediterranean saline water beetlesMOLECULAR ECOLOGY, Issue 18 2009P. ABELLÁN Abstract It has been hypothesized that species living in small lentic water bodies, because of the short-term geological persistence of their habitat, should show higher dispersal ability, with increased gene flow among populations and a less pronounced phylogeographical structure. Conversely, lotic species, living in more geologically stable habitats, should show reduced dispersal and an increased phylogeographical structure at the same geographical scales. In this work we tested the influence of habitat type in two groups of aquatic Coleoptera (Nebrioporus ceresyi and Ochthebius notabilis groups, families Dytiscidae and Hydraenidae respectively), each of them with closely related species typical of lotic and lentic saline Western Mediterranean water bodies. We used mitochondrial cox1 sequence data of 453 specimens of 77 populations through the range of nine species to compare a lotic vs. a lentic lineage in each of the two groups. Despite the differences in biology (predators vs. detritivorous) and evolutionary history, in both lotic lineages there was a higher proportion of nucleotide diversity among than within groups of populations, and a faster rate of accumulation of haplotype diversity (as measured by rarefaction curves) than in the lentic lineages. Similarly, lotic lineages had a higher absolute phylogenetic diversity, more remarkable considering their smaller absolute geographical ranges. By comparing closely related species, we were able to show the effect of contrasting habitat preferences in two different groups, in agreement with predictions derived from habitat stability. [source] On the validity of habitat as a predictor of genetic structure in aquatic systems: a comparative study using California water beetlesMOLECULAR ECOLOGY, Issue 3 2009A. E. Z SHORT Abstract Among freshwater organisms, water flow is frequently considered to be one of the most important environmental variables affecting life-history traits such as dispersal abilities and therefore genetic structure. Recent studies have suggested that habitat type alone as defined by water flow is predictive of genetic population differentiation, while others have advocated against broad generalizations in favour of more conservative, species-specific conclusions. If aquatic habitat type is predictive of population differentiation, then one would expect sympatric taxa that occupy the same aquatic habitat to converge on a similar genetic structure. We tested this prediction by examining the haplotype diversity, phylogeographical concordance, population connectivity and population isolation of three lotic water beetle species in southern California: Anacaena signaticollis, Eubrianax edwardsii and Stictotarsus striatellus. In addition to coarse habitat and geography, we also controlled for the potentially confounding factors of range size, method of dispersal and clade independence. Together, the species spanned extremes of genetic and phylogeographical structure in all measures examined, suggesting that a coarse dichotomy of aquatic habitat type is not predictive of genetic structure. While there is little question that water flow plays a major role in shaping the life-history traits of freshwater organisms, it is perilous to confer predictive properties to an artificially simplistic dichotomy or use it as a surrogate for other unmeasured variables. [source] | ||||||||||