Constant seed size and mandible growth – a fundamental problem for granivorous ground beetle larvae (Coleoptera: Carabidae)

Feeding on small tree seeds at fruit falls is a specific adaptation of harpaline ground beetles and their larvae in tropical rain forests. Using mandibles as tools, they have to perforate the seed shell to reach the nutritious interior. The isometric growth of larval mandibles, known from predatory species, would result in a changing ratio between seed and mandible size during the course of development. The stable size of host tree seeds should select an optimum mandible size, similar for the three larval instars in spermophageous species. We found an increasing tendency to maintain the length of the apical mandible part (apex) in seed feeding species.The size increase is higher in the species from Australia, Africa and South East Asia than in the New World species of the genus Notiobia. Feeding experiments have revealed that larvae of species with a stronger increase in apex growth are also able to develop as predators of Drosophila larvae. Our results furthermore point to an influence of beetle size and shell hardness of the host tree seeds on the apex size and its growth rate

Forty years of carabid beetle research in Europe - from taxonomy, biology, ecology and population studies to bioindication, habitat assessment and conservation

Volume: 100Start Page: 55End Page: 14

Ecology and adaptations of the tiger beetle Pentacomia egregia (Chaudoir) (Cicindelinae: Carabidae) to Central Amazonian floodplains.

The diurnal soil-dwelling cicindelid species Pentacomia egregia (Chaud.) inhabits Central Amazonian inundation forests. Adults pass the aquatic phase of several months duration on tree trunks. Experiments under simulated flood conditions with young beetles in climate-controlled chambers and in natural climatic conditions showed: (1) males have a shorter life span than females, (2) the mean temperature of the air influences gonad development in females but not in males, males will even copulate with immature females; (3) the presence of soil prevents gonad dormancy in females and continuous oviposition is observed. Results suggest, that the availability of soil is the primary or proximate (eco)factor which induces a rapid maturation of gonads and subsequent oviposition in females. The mean temperature of the air induces gonad dormancy and enhances longevity in females during inundation. It apparently has evolved as a cue for an adaptation to survive inundation as an ultimate factor. An increase in the mean ambient air temperature is correlated with seasonal changes in the water-level of the Solimões-Amazon River and the general climate in Central Amazoni

Spatial and temporal distribution of a tiger beetle guild (Coleoptera: Carabidae: Cicindelinae) along a 105m long transect in the reserva florestal A. Ducke near Manaus (Central Amazonia)

The spatial and temporal distribution of a guild of eight diurnal tiger beetle species was studied on a 105 m long transect near the field station of the Reserva Florestal A. Ducke near Manaus (AM), Brazil. The transect followed a path that included both shaded and an open areas. Five of the species, restricted to primary forest, occurred only in shaded areas of the transect, and three species occurred in open areas. Of all eight species only two of the open habitat species showed no clear seasonality in adult activity. In six species the activity of adults was limited to the rainy season. The most pronounced annual rhythm was found in Pentacomia ventralis, an open habitat species. Activity of adults was limited to October/November. First instar larvae appeared shortly thereafter. Larval development mainly took place from January to May. The third instar larva entered a dormancy which lasted up to 10 months, and which enabled the synchronisation of emerging adults with annual seasons

On occurrence, habitat specificity and natural history of adult tiger beetles (Coleoptera: Carabidae: Cicindelinae) near Manaus, Central Amazonia, and key to the larvae of tiger beetle genera

Over a seven year period from 1991 to 1997, 22 species of tiger beetles, representing nine genera, were recorded near Manaus, Brazil. In the whitewater floodplains along the Rio Solimoes-Amazonas (Ilha de Marchantaria), three diurnal species inhabit inundation forests and six species (two diurnal, four nocturnal) live in open areas. Data on their natural history and adaptation to living conditions in floodplains are presented. Fifteen species were located on non-flooded uplands (Reserva Florestal A. Ducke). Five diurnal species inhabit the forest floor, two species are canopy dwellers, and eight species (seven diurnal, one nocturnal) live in open areas on whitesand or laterite. Only one species, Pentacomia lacordairei, was found in both floodplain and upland forests. A key to the larvae of tiger beetle genera located near Manaus is presented

Arthropods obtained from the Amazonian tree species "Cupiuba" (Goupia glabra) by repeated canopy fogging with natural Pyrethrum

Two canopies of a widely distributed Amazonian tree species, Goupia glabra Aubl. (Celastraceae, height 38 and 45m) were fogged several times with 1% natural pyrethrum during the rainy and dry seasons (1991-1994) in the Adolpho Ducke Forest Reserve near Manaus/Brazil. Between 50 and 158 ind./m2 of arthropods were obtained per tree and fogging event. Hymenoptera, mostly Formicidae, and Diptcra dominated. A total of 95 ant species occurred on a single tree. Most ants were permanently foraging in the canopy and their recolonization after fogging seems to follow stochastic pathways. Data indicated an interaction between - 1) predating Formicidae and gall building Cecidomyiidae and - 2) Cecidomyiidae and the parasitic Hymenoptera