Host plant utilization and population abundance of three tropical species of Cassidinae (Coleoptera: Chrysomelidae)

Considering the little information on the biology and phenology of Chrysomelidae beetles and interaction with their host plants, we have followed the populations of Stolas chalybea, S. areolata and Anacassis phaeopoda for 2 years in order to obtain basic biological data on them and to describe their occurrence throughout the year. After emerging from the eggs, larvae of the three studied species remained aggregated, although the size of the groups decreased as the larvae developed. Egg clusters and young larvae of the two Stolas species were more frequently found on the underside of leaves of their host plants and mature larvae of S. areolata were only observed on the upper side of leaves. Adults of the three species were always isolated and both Stolas species were more frequently found on the upper side of leaves. The number of new branches on the host plant and some other plant physical characteristics were significantly related to Cassidinae abundance. The three studied species became active with the end of the dry season, reproduced more intensely during the rainy season and reduced their activity with the lowering of temperature and rainfall. The beetles also showed a lower peak of egg laying at the end of diapause of adults. This pattern of occurrence was very similar to the occurrence of leaves, especially the newest ones, on their host plants. Significant positive correlations between Cassidinae numbers and temperature showed that this parameter could influence ovipositing and mating activities.     

Seasonal patterns of arthropod diversity and abundance on big sagebrush, Artemisia tridentata

The sagebrush biotype is the largest in the western United States. This vast sagebrush community is thought to harbor equally vast and diverse arthropod communities, but these remain little explored. Our objective was to examine the diversity, abundance, and seasonal phenology of arthropod taxa found on the dominant shrub of the sagebrush ecosystem, big sagebrush ( Artemisia tridentata ). We wanted to improve understanding of this little-studied arthropod assemblage that may play significant roles in the dynamics of sagebrush populations and the sagebrush ecosystem. We sampled free-living and gall-forming arthropods from a stratified random sample of sagebrush plants at the Barton Road Ecological Research Area, Idaho, resulting in a sample of over 8000 individuals and 232 morphospecies. Species richness and abundance declined from May to August, and abundance of most taxa similarly declined over the summer. A few taxa, including Acari (mites), were notably more abundant in August. Fluid feeders were the most diverse and abundant free-living feeding guild during all months and comprised up to 79% of morphospecies. The gall formers included 4713 individuals of 12 species of gall flies ( Rhopalomyia spp.), primarily (97%) R. ampullaria. Abundance of galls increased from small to large (presumably young to old) plants. Overall, A. tridentata was host to a high diversity of arthropods, some of which have potential to cause or mitigate significant damage to their host plant. Arthropods seem likely to have the greatest impact on sagebrush early in the growing season, when they are most diverse and abundant. Documentation of the full diversity of arthropods associated with sagebrush required samples taken throughout the growing season, but a single sample early in the growing season captured a high proportion of taxa.     

Age-related body weight,fecundity and population change in a south Dorset sika population (Cervus nippon); 1985–1993

Density-related changes in performance have been documented for a number of different ungulate species, with recorded decline in body weight, fecundity and both juvenile and adult survival as population densities increase. While density-dependent responses of this kind have been explored in some detail in red, roe and fallow deer, little published information is available on demographic responses to density in European populations of sika deer (Cervus nippon). This paper offers an analysis of the dynamics of two populations of sika from the south of England from 1985–1993. Data on age-related body weights for males and females and pregnancy rates of females are taken from analysis of cull records of 321 males and 534 females culled during that 8-year period. We describe trends in body mass of adult and juvenile sika of both sexes, and consider changes in pregnancy rates of both mature and yearling females in relation to changes in relative abundance. Despite steadily increasing population density between 1985 and 1991/1992, no consistent decline was recorded in body weight or condition (as measured by % cover of kidney fat) for calves or yearlings of either sex, or for mature females. A decline in recorded body weight of adult males was not significantly correlated to ranked relative abundance. Fecundity was high (with > 90% of mature females sampled found pregnant). Most mature females found pregnant were also lactating. The proportion of animals that conceived as yearlings (72%) was lower than that recorded for more mature hinds; however there is some indication that the difference recorded may simply reflect the fact that yearlings may conceive later in the season than older animals. No significant differences were apparent in the proportion of either adult or yearling females found pregnant in different years.     

Ringing studies of the turtle dove Streptopelia turtur (Aves: Columbidae during passage through Antikythera Island,southwestern Greece

The aim of this study is to describe the phenology of migration and biometrics of the turtle dove Streptopelia turtur in Greece, based on ringing studies on Antikythera Island. Spring passage takes place between early April and late May and autumn passage between early and late September. There is no significant difference in either wing length or tarsus length between adults and juveniles. Males have significantly greater wing length. There is no significant difference in tarsus length between the two sexes.     

Leucocytozoon toddi in British sparrowhawks Accipiter nisus: observations on the dynamics of infection

Leucocytozoon infection was studied in a breeding population of sparrowhawks Accipiter nisus in the British Midlands. Almost all transmission was apparently ‘vertical’ from adults to young, at the nest site. Parasites largely disappeared from the blood between October and April, reappearing in a ‘spring relapse’ during the nesting season. Infected birds remained infected for life; there was no evidence of reduced longevity in infected birds once they had dispersed from their natal nest site. There was no assortative mating between infected or uninfected males and females. It is postulated that the concentration of birds at the nest site allows transmission by a non-specific vector breeding in the same vicinity. At other times of year the birds are more regularly dispersed and transmission in unlikely to occur.     

Population dynamics of the bark-dwelling spider Eustala perfida Mello-Leitão, 1947 (Araneidae)

Population dynamics of spiders may vary according to biotic and abiotic factors. We studied the phenology of the bark-dwelling spider Eustala perfida over a two-year period and investigated how temperature, precipitation, and prey availability were associated with the population of this species. The population of E. perfida presented a well-defined fluctuation, with one reproductive cycle per year. The recruitment of spiders occurred in summer, followed by successive phenological peaks at all stages of development. The species is protogynic, and the population of adult males peaks in the cold/dry season, indicating a winter mature phenological pattern. The diet of E. perfida is composed mainly of medium-sized homopterans, complemented by small dipterans and hymenopterans. We found that the higher abundance of spiders occurred two months after the highest values of precipitation and temperature, and three months after the higher abundance of potential prey items. These results indicate that spiders require time to respond to changes in environmental conditions. The species’ natural history and the structure of the trunks in which it lives may also affect the number of individuals in a particular area and over time.     

Biology and conservation of the Coral Pink Sand Dunes tiger beetle, Cicindela limbata albissima Rumpp

This study investigated the distribution, abundance, and biology of Cicindela limbata albissima Rumpp, an endemic tiger beetle known only from the Coral Pink Sand Dunes (CPSD) in southwestern Utah. A recently implemented conservation agreement between BLM, USFWS, Utah State Parks, and Kane County protects most of the known habitat of this beetle from off-highway vehicle (OHV) use. A search of collection records and field surveys of 19 Great Basin sand dune sites indicated that this species occurs only at CPSD. Yearly index counts of adults (1992-1998) during peak season in May ranged from 331 in 1997 to 895 in 1993, but the actual population size is probably 2-3 times higher than the index counts. Nearly all of the population is found in the primary habitat, a 300-m-wide × 2.7-km-long area in the southern part of the dune field. Small numbers of adults and larvae have been found at the far north end of the dune field. Mark-recapture studies indicated that most adults moved only short distances ( Surveys of dominant plant species, arthropod (potential tiger beetle prey) abundance, and OHV activity indicated that these vary throughout the dune field and may explain, in part, the distribution of C. l. albissima . The primary habitat is a transition area between the highly dynamic south end of the dune field and the more stabilized north end. Psoralidium lanceolatum Rybd., Sophora stenophylla Gray, and Stipa hymenoides R.&S. are the dominant plants in the interdunal swales of the primary habitat, but other species are dominant in other parts of the dune field. Numbers of arthropod individuals and taxa are greatest in the primary habitat. Off-highway vehicle activity was greatest at the south end of the dune field and lowest at the far north end. Run-over trials and observational data revealed that adult beetles are killed by OHVs, but more important impacts may be damage to vegetation, reduction of arthropod prey of C. l. albissima , and disturbance and increased desiccation of the larval microhabitat. We anticipate that the conservation agreement will provide long-term protection for this species at CPSD.     

Carnivorous Nepenthes pitcher plants are a rich food source for a diverse vertebrate community

Carnivorous pitcher plants capture insect prey to acquire essential nutrients while growing on extremely poor soils. A few individual species have evolved mutualistic relationships with small mammals that visit the traps to harvest nectar, and in return leave faecal droppings in the pitchers. Here we report that a diverse guild of nectar-harvesting vertebrates visits pitchers of two common lowland Nepenthes species without providing any obvious benefit for the plants. Over four consecutive field seasons, we observed four species of sunbirds and one species of tree shrew drinking nectar from pitcher plants. Foraging activity was highest in the morning and late afternoon. Van Hasselt’s, Brown-throated and olive-backed sunbirds were regular and highly abundant pitcher visitors in two different field sites. A crimson sunbird and a lesser tree shrew were each observed harvesting nectar on one occasion. The vertebrates harvested nectar from the pitcher rim (peristome) of N. rafflesiana and from the underside of the pitcher lid of N. gracilis. A comparison of the nectar production of these and three further sympatric species revealed exceptionally high quantities of nectar for N. rafflesiana. Other factors such as plant and pitcher abundance and the habitat preferences of the observed vertebrates are likely to also play a role in their choice to visit particular species. This is the first account of a case of obvious nectar robbing from Nepenthes pitchers by a guild of species that are too large to serve as prey, while the pitcher size and shape prevent faecal droppings from reaching the pitcher’s inside. This interaction provides an example of a possible starting point for the evolution of the elaborate mutualistic relationships observed in some species. Follow-up adaptations of pitcher shape could enable the plants to catch the droppings of their visitors and turn an exploitative relationship into a mutualism.     

Biology and defensive secretion of myrmecophilous Thiasophila spp. (Coleoptera: Staphylinidae: Aleocharinae) associated with the Formica rufa species group

Various aspects of the biology of the myrmecophilous Thiasophila angulata and T. szujeckii (Staphylinidae; Aleocharinae), mainly associated with the Formica rufa species group, are studied. The composition of defensive gland secretions from adults of T. angulata has been analysed. The complete development (egg-L_1-3-pupa-adult form), including adult overwintering, of both species takes place solely in ant nests. Under laboratory conditions, this lasts for about 22 days in T. angulata, and the period elapsing between the old and new generations of insects is approximately two months. The mean fecundity of adults of this species (28 eggs) was determined, as well as the duration of its reproductive period (mean 28.5 days), and lifespan (mean 67 days). In natural conditions T. angulata, found within nests of Formica polyctena and F. rufa, produces three generations, and the sibling species T. szujeckii one generation per year. These two species differ in their phenologies and abundance dynamics of adults and larvae, which is linked to the size and temperature regime of the host nest. The results of this study uphold the recent separation of T. angulata and T. szujeckii based on morphological features of adults and selected molecular markers. Adults and larvae of T. angulata forage on both live and dead food items accumulated by the host, as well as on the host’s eggs and larvae. Both the beetle larvae and adults remain unmolested among the host workers. The adults use their defensive gland secretions, which contains substantial quantities of toxic quinones, when necessary. According to the current categories of myrmecophiles, T. angulata (and by analogy, T. szujeckii as well) should be classified as a species wholly integrated with the host.     

Year-round activity patterns in a hyperdiverse community of rainforest amphibians in Madagascar

Madagascar hosts a high diversity of amphibians estimated at over 500 species, nearly all of them endemic. Surprisingly few data are available on the activity cycles of this fauna, despite its importance for ecological, evolutionary and conservation research. Here we report the results of a year-round survey of amphibians along a transect bordering the Analamazaotra forest near Andasibe in central eastern Madagascar. During 120 transect walks evenly spaced through the year, a total of 2530 individuals of 40 species of anurans was observed. Abundance was higher during the warm/rainy season (December to April) and peaked in February. Of the five climatic predictors measured, only mean temperature and relative humidity showed high importance values, and multi-model averages indicate that these two variables have a strong effect on amphibian abundance along the transect. Species richness showed no evident peak during the study period and was best explained by a model including average temperature and rainfall. Canonical correspondence analysis indicates that Boophis sibilans, B. tephraeomystax, B. boehmei and Plethodontohyla notosticta were more frequently encountered along the transect on cold and humid days while Plethodontohyla mihanika, Gephyromantis boulengeri and Spinomantis aglavei were distinctly more abundant on cold and dry days, and Paradoxophyla palmata on warm and dry days. The results of our study flag a number of species as suitable candidates for future monitoring initiatives and suggest that a simple combination of visual and acoustic surveys can estimate amphibian activity with high sample sizes in Madagascar’s rainforests.     

Field studies of Cybocephalus nigriceps nigriceps (J. Sahlberg) (Coleoptera: Cybocephalidae) in Israel

Summary

Cybocephalus nigriceps nigriceps (J. Sahlberg) reproduces in Elat (the Arava region of Israel) during spring and summer. Eggs and larvae are present on date palms during these seasons only, whereas adults occur in the grove throughout the year. The adult population reaches its peak in mid-summer and decreases considerably during spring and autumn. Two main locations in which adults occur during the seasons, were found on date palm trees.

Due to the lack of reproduction and activity during autumn and winter, the predator takes almost no part in the biological control of the parlatoria date scale in these seasons.     

Role of livestock and black-tailed jackrabbits in changing abundance of Kochia americana

Normal 0 false false false EN-US X-NONE X-NONE MicrosoftInternetExplorer4 st1\:*{behavior:url(#ieooui) } /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin:0in; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi;} Historical accounts and matched photographs indicate sharp decline of once-abundant Kochia americana in eastern Great Basin vegetation since the early 1900s, most of the decline by the late 1950s. Exclosure data show further decline from 1957 to 1973, then some increase between 1970 and 1973 and 1976 and 1981. Utah sheep numbers, at maximum from 1925 to 1940 and declining steadily to the 1970s, may have induced the long-term changes. Black-tailed jackrabbits ( Lepus californicus ), could not have induced vegetation decline, but could have added to livestock pressure and abetted the trend. In 1972, rabbits near a cyclic high were indirectly estimated to completely utilize K. americana in Curlew Valley, northwestern Utah. In 1976–1977 at rabbit low, direct measurements show 4%–18% of plants browsed by late summer, about 30%–50% of herbage removed from browsed plants. The latter rose to 45%–82% by end of winter. Late-summer percent browsed may have risen slightly (11%–21%) in 1980–1981 at next rabbit high. Increase in K. americana density from 1973 to 1976, then a slight decrease from 1976 to 1980, suggests fluctuating K. americana abundance induced by rabbit browsing, superimposed on long-term K. americana decline and recovery.     

Population dynamics,age structure and sex ratio of the bromeliad-dwelling jumping spider,Psecas chapoda (Salticidae)

In this study, the population fluctuations, phenology and sex ratio of the bromeliad-dwelling jumping spider Psecas chapoda were investigated in an area of semi-deciduous forest in south-eastern Brazil. Psecas chapoda occurred and reproduced on Bromelia balansae (Bromeliaceae) throughout the year. The number of egg sacs increased at the beginning of the rainy season (September to December), but the population size and phenology were stable over time and correlated weakly with rainfall and temperature. The principal factor affecting the dynamics of P. chapoda was the blooming of B. balansae, which expelled spiders because of the drastic change in plant architecture. Male spiders were more frequent than females during the juvenile phase, whereas females were more frequent than males during the subadult and adult phases, suggesting a sex ratio that favoured males. The biotic and abiotic factors that influence the population dynamics and sex-dependent vulnerability determination are discussed.     

Thermal ecology and activity patterns of the short-horned lizard ( Phrynosoma douglassi ) and the sagebrush lizard ( Sceloporus graciosus ) in southeastern Idaho

A mark - recapture study of the short - horned lizard ( Phrynosoma douglassi ) and the sagebrush lizard ( Sceloporus graciosus ) was performed from 1976 to 1977 in southeastern Idaho. Both species had mean cloacal temperatures of approximately 33 C. However, P. douglassi had more variable cloacal temperatures, particularly during morning and evening periods. This was caused by differences in sleeping sites chosen by the two species. Adults of both species were active from mid - April through late August, with peak activity in June. Juvenile P. douglassi displayed a seasonal activity pattern similar to that of adults. Juvenile S. graciosus were most active later in the year (August), when adults were disappearing. In both species, young - of - the - year appeared in early to mid - August. Adult and juvenile P. douglassi were active during all daylight hours and displayed no activity peaks, whereas young - of - the - year displayed a bimodal activity pattern. Adult and juvenile S. graciosus were active over all daylight hours but had peak activity between 1200 and 1500 h. Ants ( Pogonomyrmex ) were the lizard's principle prey. However, only young - of - the - year P. douglassi had activity patterns that paralleled that of ants on their mounds.         

You are what you eat: native versus exotic Crotalaria species (Fabaceae) as host plants of the Ornate Bella Moth,Utetheisa ornatrix (Lepidoptera: Erebidae: Arctiinae)

Crotalaria plants and Utetheisa ornatrix are closely linked to each other: the larvae destroy the seeds, while the moth depends on hostplants for alkaloids. To better understand the ongoing co-evolution, the present study examines how native hostplants compare to exotic ones. Leaf-feeding on Crotalaria pumila, C. rotundifolia, and C. incana, native to the moth’s range, led to faster larval development than on the exotic C. lanceolata, C. spectabilis, and C. pallida. Seed-feeding on all species of Crotalaria led to accelerated larval development and a resultant larger adult moth, and correlates with a higher nitrogen content in the plant tissues. These results add a novel dimension to the previous studies of reproductive biology of this model organism. In controlled settings, mature larvae showed preference for leaves of C. spectabilis over those of other species, perhaps due to the higher alkaloid content. Differences in morphology and phenology of Crotalaria determine the ecology of U. ornatrix populations in Florida. The introduction of novel hostplants, on which U. ornatrix can have a significant negative effect and which are of concern to humans as invasive toxic weeds, has greatly expanded the niche occupied by this moth. Possible co-evolution of Utetheisa sensu lato and plant defences in the genus Crotalaria is discussed.     

Life history, abundance, and distribution of Moapa dace ( Moapa coriacea )

Moapa dace ( Moapa coriacea ) is a federally listed endangered fish endemic to the spring-fed headwaters of the Muddy River, Clark County, Nevada. Species life history, abundance, and distribution were studied from March 1984 to January 1989. Reproduction, which was observed year-round, peaked in spring and was lowest in fall. It occurred in headwater tributaries of the Muddy River within 150 m of warm water spring discharge in water temperatures ranging from 30 to 32 C. Females matured between 41 and 45 mm in fork length (FL). Egg abundance increased with female size ( r 2 = .93); counts ranged from 60 for a 45-mm-FL female to 772 for one 90-mm FL. The oldest of eight fish, aged by the opercle method, was a 90-mm-FL, 4+-year-old female. Adults are omnivorous but tended toward carnivory; 75% of matter by volume consumed was invertebrates and 25% plants and detritus. Fish size was generally commensurate with flow, the largest fish occurring in the greatest flow. Adults were near bottom, in focal velocities ranging from 0 to 55 cm/s. Juveniles occupied a narrower range of depths and velocities than adults, and larvae occupied slack water. From December 1984 to September 1987, the total adult population ranged from 2600 to 2800. Although these numbers are higher than previously believed for Moapa dace, they are still sufficiently low to warrant its endangered status. The dependency of Moapa dace's different life history stages to various areas and habitat types of the Warm Springs area suggests that all remaining habitat is necessary for their survival.     

Seasonal occurrence and adaptation of the exotic Glycaspis brimblecombei Moore (Hemiptera: Aphalaridae) in Italy

Alien insects usually adapt their phenology and their needs to the environment into which they are introduced. During 2010, the red gum lerp psyllid, Glycaspis brimblecombei, was accidentally introduced into Italy, becoming an invasive pest of Eucalyptus L’Hér. Eucalypts are very common in Italy as ornamental and forest species. The seasonal adaptation of the psyllid was studied at three field sites. G. brimblecombei showed a seasonal population dynamic, suggesting that many generations occur during the year and the species overwinters in all stages without diapause. The population size in the new area of colonization is affected by low winter temperatures, but also by high temperatures in the absence of rainfall. In Lazio, the specific parasitoid Psyllaephagus bliteus was collected for the first time.     

Winter and early spring bird communites in grasslands, shrubsteppe, and juniper woodlands in central Oregon

We compared winter (December, January, and February) and early spring (March and April) bird communities among 4 successional stages that included grassland, shrubsteppe, juniper-shrubsteppe, and old-growth juniper woodland in central Oregon. Birds were surveyed monthly from December through April in 1998/1999 and 1999/2000 using the point count method to estimate relative abundance of birds (individuals ? transect –1 year –1 ). We used distance sampling to correct for potential bias in estimating abundance and density among successional stages. A total of 4513 birds (32 species) were detected. Relative abundance of total birds (all species combined) was similar in the juniper-shrubsteppe and old-growth woodland (48.7 and 48.9 individuals ? transect –1 , respectively) but 6 times greater than in the grassland and shrubsteppe (8.0 and 7.7 individuals ? transect –1 , respectively) during the 5-month period. Total density of birds was greater in old-growth juniper woodland and juniper-shrubsteppe than in grassland or shrubsteppe. However, median bird species richness in 1998/1999 was highest in grassland and lowest both in shrubsteppe and juniper-shrubsteppe, and in 1999/2000 it was highest in shrubsteppe and lowest in juniper-shrubsteppe and oldgrowth juniper woodland. American Robins and Townsend's Solitaires were the most abundant species in junipershrubsteppe and old-growth juniper woodland during the winter months. Sage Sparrows and Horned Larks were the most abundant species in shrubsteppe during winter, and Horned Larks were most abundant in grasslands during the early spring transition period prior to nesting. Our results indicate that a different suite of species use these successional stages during the nonbreeding season. If avifauna conservation is a part of long-term management goals, a broad range of successional stages should be maintained on the landscape to provide habitat for a variety of avian species throughout the year.     

The diet of the Eleonora’s falcon (Falco eleonorae) in the Aegean archipelago (Greece)

ABSTRACT

In the present study we investigated the diet of Eleonora’s falcons in Greece and assessed the regional dietary pattern of 16 breeding colonies of the Aegean. Overall 224 nests were visited and a total of 8067 prey items were collected which contained two mollusca classes, seven insect orders, one reptile family, two mammalian taxa and at least 54 avian species. Cicadas were the most common insects found in pellets (45.1%) followed by flying ants (34.8%) and beetles (15.8%) while just 20 species (33.3%) accounted for over 90% of the avian prey items identified in bird remains dominated (>50%) by the Willow Warbler (Phylloscopus trochilus), the Red-backed Shrike (Lanius collurio) and the Whitethroat (Sylvia communis). Insect feeding peaked in late August (39.8%) and late September (20.8%), whereas bird remains built up in falcon nests from mid-August onwards, culminating in late September (57.2%) and declined abruptly afterwards. Overall the falcons’ diet diversity increased as the breeding season progressed and from the north towards the south Aegean. The avian prey species richness was negatively influenced by the distance of the colonies from the mainland and the weather conditions during September which coincides with the fledgling period of the young and the autumn peak of passerine migration.     

Ecology and behaviour of the ‘road tarantulas’ Eupalaestrus weijenberghi and Acanthoscurria suina (Araneae,Theraphosidae) from Uruguay

Spatial distribution, burrow morphology, phenology, defensive displays and predation of two theraphosid spiders living in meadows were studied in Uruguay. Exhaustive field studies complemented with laboratory observations were carried out. Eupalaestrus weijenberghi occurred throughout the country while Acanthoscurria suina occurred only in the southern half. Both species seemed to be the most abundant theraphosid spiders in Uruguay as they live in the dominant landscape of the country. Burrows from both species showed a similar morphological pattern but a terminal narrow tube was found only in E. weijenberghi. We observed that A. suina always co‐occurred with E. weijenberghi but this species frequently occurred in the absence of the former. When co‐occurring A. suina showed an aggregated distribution while E. weijenberghi was randomly distributed. A restricted reproductive period was found for both species, mainly between March and April, evidenced by the massive presence of walking adult males and then confirmed by pit‐fall traps. Moulting, oviposition and longevity were also studied. Conspicuous species‐specific defensive behaviours were displayed by the tarantulas in all cases, when collected. These tarantulas showed spatial co‐occurrence and temporal coexistence with the beetle Diloboderus abderus, an important pest of grasslands. Tarantula predation on adult beetles was confirmed, these spiders being one of the few beetle predators. Their maximal efficiency in beetle predation could reach 65?000 prey captured per hectare by month. These polyphagous tarantulas seem to be potential agents for the biological control of beetle pests.