Aims: The fauna of mountains and their surrounding regions are likely to be influenced principally by two biological processes: horizontal colonization along similar altitudinal levels by elements ...originating from lineages inhabiting higher latitudes; and vertical colonization by lineages from the same latitude, but at lower altitudes. We examine whether the expected patterns derived from the latter process can be observed in mountain dung beetle assemblages. Specifically, we study the variation in species composition and richness with altitude in five regions spanning elevation gradients, analysing whether the altitudinal rates of change in the number of species and genera differ, and whether beta-diversity scores for adjacent sites in each altitudinal gradient are different for species and genera. Location: Eastern Cordillera of the Colombian Andes. Methods: Field work was carried out in 1997-99 at 27 sites in five regions with elevation gradients, with 10-32 pitfall traps placed in each site. For each altitudinal level the numbers of species and genera were analysed with respect to altitude, and the slope of the linear regression between these variables was calculated. The slope of the curve of the altitude against the cumulative number of species and genera was also calculated for each altitudinal gradient to describe the compositional change between adjacent sites (beta diversity). Species and generic slopes were compared using analysis of covariance. The turnover of species along each altitudinal gradient was measured using presence/absence data and Cody's beta-diversity index between adjacent pairs of sites. A cluster analysis was used to detect faunistically homogeneous groups of localities. Results: Species richness always decreased with altitude, although the slopes did not differ significantly from zero. The number of genera also decreased with increasing altitude, but generally at a significantly slower rate than for species. Variation in the species beta-diversity scores between altitudinal levels did not follow a homogeneous pattern in the different regions. Two main altitudinal groups of sites with a boundary c. 1500-1750 m a.s.l. can be detected with respect to faunistic similarity. Low- and mid-altitude sites are inhabited by all of the genera (19) and 80% of all species collected. Eight genera and 61 species (c. 60% of the total) are unable to inhabit high-altitude sites, and only 20 species appear to be exclusive to these high-altitude environments (> 2000 m a.s.l.). Main conclusions: The dominant processes explaining dung beetle composition in the high north-eastern Andean mountains are probably those of vertical colonization. The limited role of horizontal colonization processes, or colonization from northern or southern lineages, could be a consequence of the isolation and recent geological origin of these mountains.
Soil biological processes that produce greenhouse gases, such as N sub(2)O, are more intense in tropical soils because of the warm and humid climate; however, the role played by the wide diversity of ...fauna in these soils in soil N sub(2)O production is still poorly understood. This study attempts to assess the role of scarabaeid grubs (Coleoptera), a major faunal group in tropical soils, in emissions of atmospheric N sub(2)O. It was hypothesized that (i) the guts of these grubs are important sites of N sub(2)O-genesis, since they present environmental conditions (anoxia, high labile C and N mineral contents) that are suitable for N sub(2)O production; and (ii) rates of N sub(2)O emissions will vary according to the density of gut microbial communities that are involved in N sub(2)O emission (i.e. ammonia-oxidizers and denitrifiers). Through laboratory microcosm experiments, in vitro emissions of N sub(2)O were determined directly from live grubs of different scarabaeid species (collected from tropical soils of Madagascar and Mexico) and from their surrounding parent soils. Quantitative PCR was used to determine the abundance of the total bacterial community (using the 16S rRNA gene) as well as the ammonia-oxidizing (bacterial AOB and archaeal AOA) and denitrifying (nirK, nirS and nosZ) microbial communities in the grub guts and surrounding soils. The mineral N contents of grub guts and parent soils were also determined using a continuous flow analysis technique. All of the studied grub species emitted significantly higher N sub(2)O than the parent soils and presented a high gut ammonium to nitrate ratio (16:1). Their guts harbor a higher density of total bacterial (4.5-fold) and nitrite reductase (nirK) genes (1.5-fold) than the parent soils. However, with the exception of nirK, the relative and absolute abundances of all ammonia-oxidizer and denitrifier genes were higher in soils than in the grub gut environment. The average gene abundance of AOA was 10-fold higher than that of its bacterial counterpart (AOB). Emission of N sub(2)O from grubs correlated significantly with the gene abundance of their gut ammonia-oxidizers (AOA and AOB) and denitrifiers (nirS), but not with mineral N contents. Based on average biomass values, these scarabaeid grubs are estimated to contribute between 0.2 and 1.8% of total soil N sub(2)O emissions in tropical areas.
Bezděk & Sehnal,
, from Somaliland is described and relevant diagnostic characters are illustrated. The new species is compared with the morphologically closely similar
Kolbe, 1894 species. An ...updated checklist and an identification key to northeastern African
species are provided.
Aim: We describe the changes in species richness, rarity and composition with altitude, and explore whether the differences in Scarabaeinae dung beetle composition along five altitudinal transects of ...the same mountain range are related to altitude or if there are interregional differences in these altitudinal gradients. Location: Field work was carried out on the eastern slope of the eastern Cordillera, Colombian Andes, between Tama Peak to the north, in the Tama National Park (07 degree 23' N, 72 degree 23' W) and the San Miguel River (00 degree 28' N, 77 degree 17' W) to the south. Methods: Sampling was carried out between February 1997 and November 1999 in five regions spanning elevation gradients. In each gradient, six sites were chosen at 250 m intervals between 1000 and 2250 m a.s.l. Results: We found a curvilinear relationship between altitude and mean species richness, with a peak in richness at middle elevations. However, the diversity of dung beetle assemblages does not seem to be related to the interregional differences in environmental conditions. The number of geographically restricted species is negatively and significantly related to altitude, with geographically restricted species more frequent at low altitude sites. Ordination delimited the two main groups according to altitude: one with all the highest sites (1750-2250 m a.s.l.) and a second group with the remaining sites (< 1750 m a.s.l.). Analysis of species co-occurrence shows that these dung beetle assemblages seem to be spatially structured when all sites have the same probability of being chosen. In contrast, the spatial structure of species assemblages seems to be random when the probability of choosing any site is proportional to its altitude. Main conclusions: The altitude of sites is the main factor that influences the diversity of these dung beetle assemblages. The peak in species richness at middle elevations, the higher number of geographically restricted species at lower altitudinal levels, and the compositional differences along these mountain gradients seem to result from the mixing at these altitudes of dung beetle assemblages that have different environmental adaptations and, probably, different origins. The relevance of altitude in these assemblages is related to the limited role of these Neotropical high altitude environments as centres of refuge and vicariance for a monophyletic group of warm-adapted species, for which the vertical colonization of these high mountain environments by lineages distributed at lower altitudes would have been very difficult.
Sublethal effects of NeemAzal super( registered )-T/S (1 % azadirachtin A) on female cockchafers were studied in two experiments with caged beetles. The beetles were collected in early spring whilst ...leaving the soil after hibernation. At that time, they had not fed before and they were virgin. The beetles were kept singly in plastic boxes and provided with treated leaves at different stages of egg maturation. The amount of food consumed and the progression of body weight were recorded daily, whereas the state of oogenesis was surveyed at defined intervals. It was shown that food consumption, body weight development and egg maturation were affected by the uptake of azadirachtin-treated plant material compared to beetles from control groups. In no-choice experiments, azadirachtin-treated leaves were accepted readily and feeding was reduced by 60-70 % compared to females fed with untreated foliage. Recovery by feeding on untreated leaves after the uptake of contaminated foliage was either not evident or at a very low level. Moreover, egg maturation was interrupted when females were fed with azadirachtin-treated leaves during the process of oogenesis. If egg maturation was accomplished at the time of first uptake of azadirachtin-treated plant material, caged females were able to lay as many eggs as females from the control group, the egg hatching rate was not affected, and there were no signs of morphological malformations in the freshly hatched L sub(1)-larvae.
Scarabeoidea (Insecta: Coleoptera) present more than 2000 species recorded from all over Brazil. They have been scarcely recorded from caves, and truly troglobitic species are yet to be found in the ...country. In this study, we carried out a review of all existing scarab beetles deposited until 2017 in the Coleção de Invertebrados Subterrâneos de Lavras (ISLA), at the Universidade Federal de Lavras (UFLA) (Minas Gerais, Brazil), one of the most important collections of subterranean invertebrates in South America. Ninety-two individuals belonging to 52 species were recorded, distributed in six families (Cetoniidae, Hybosoridae, Melolonthidae, Passalidae, Scarabaeidae and Trogidae). Scarabaeidae was the most diverse of them, representing more than 50% of the total of species recorded. We found Scarabeoidea beetles in 51 of the ~ 1600 caves examined, distributed in nine Brazilian states: Alagoas, Bahia, Distrito Federal, Espírito Santo, Goiás, Minas Gerais, Pará, Piauí, and Tocantins. Our results provide evidence that Scarabaeoidea beetles are not frequent in Brazilian caves, and their records in this kind of environment are mostly accidental. Exceptions include Trogidae and Aphodiinae species, which may be associated with bat guano. Our study presents the first list of Scarabaeoidea species sampled in Brazilian caves.
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