The genus Typhlocharis Dieck 1869 (Coleoptera: Carabidae): description of a new species from Portugal and remarks on the external microsculpture of the last abdominal sternum “belt”

The endogean carabid Typhlocharis zaballosi n. sp., belonging to the T. gomezi group, is described and illustrated. The work provides diagnostic characters, in particular the structure of male and female genitalia, affinities to putative relatives and some remarks on its ecology and distribution. A key for the identification of all known species of the T. gomezi species group are provided. Some remarks on the external microsculpture of the last abdominal sternum “belt” of T. carinata Serrano & Aguiar 2006, T. quarta Pérez-González & Zaballos 2013, T. crespoi Serrano & Aguiar 2007 and T. zaballosi n. sp. are given. An overall revision of the presence/absence of this structure in the genus is provided and its taxonomic relevance is also discussed.     

Seasonality and life histories of two endemic New Zealand carabid beetles (Coleoptera: Carabidae): Mecodema oconnori Broun and Megadromus capito (White)

Abstract

Seasonal activity and life histories of two large endemic carabid beetles, Mecodema oconnori Broun and Megadromus capito (White), were investigated in two lowland forest remnants in the Horowhenua region, North Island, New Zealand. Seasonal activity was estimated from manual searches of surface refuges, plus pitfall trapping from October to March. Adults of both species were present throughout the year, although M. oconnori was much more abundant in spring. Megadromus capito larvae were caught from October to March, and the three instars overlapped temporally, implying a long period of larval emergence and development. Adult females were dissected to investigate their reproductive phenology. Both species carried eggs for at least 6 months of the year. M. oconnori females contained very few eggs, with a maximum of three eggs each and a mean of 1.6 eggs per female. Mg. capito females had up to 28 eggs each and a mean of 10.5. Both species appear to have low egg loads, a relatively long period of reproductive activity and long life spans, but longer‐term studies on the pre‐adult stages and reproductive activity of adults are required to complete understanding of their life cycles.     

Mechanical reproductive isolation via divergent genital morphology between Carabus insulicola and C. esakii with implications in species coexistence

The mechanical isolation hypothesis predicts that physical incompatibility between divergent reproductive morphologies hinders hybridization between populations. However, evidence for this hypothesis remains scarce. We examined this hypothesis using two parapatric carabid beetles, Carabus insulicola and C. esakii, which are of the subgenus Ohomopterus and exhibit a species-specific genital lock-and-key system. Our interspecific crossing experiment revealed that incompatibility of genital morphologies served as a strong postmating-prezygotic isolation barrier. This isolation was asymmetric: a decrease in female fitness was more costly in the cross with greater genitalic incompatibility between a C. esakii female and a C. insulicola male. These two species share a limited sympatric area, but the mechanism responsible for their coexistence is unclear given no evidence of premating isolation via male mate choice. A comparison of the present results with those of previous studies that quantified reproductive isolation between Ohomopterus species suggest that strong mechanical isolation via genitalic incompatibility plays a major role in species isolation, but that it may be less important in species coexistence.     

The control of reproductive diapause in Nebria salina (Coleoptera: Carabidae)

Abstract. 1. Adult male and female Nebria salina were collected in summer, when in reproductive diapause, and subjected to three different photoperiod regimes, LD 18:6 h, LD 12:12 h, and LD 6:18 h, to assess the role of light regimes on sexual development. 2. Two alternative hypotheses were tested: (i) development rates increase in response to time restriction and (ii) development rate is at a maximum on the day length approximating to that in the field during reproduction. 3. Gonad development was assessed after 1 and 2 months' exposure to the experimental day lengths. In female N. salina, photoperiod and length of time of exposure both influenced reproductive development. Females required at least 2 months' exposure to photoperiods of ≤ LD 12:12 h to mature. Development of the ovary did not take place on LD 18:6 h, irrespective of the length of exposure. Sexual development occurred in all the males after 2 months, irrespective of photoperiod. 4. At the end of the study the activity of the remaining beetles was measured and compared. Significantly higher activity levels were measured in periods of darkness, and consequently beetles exposed to the two shorter day lengths were found to be more active than those kept on the longest photoperiod. Comparing the 3‐h period 06.00 – 09.00, the last 3 h of darkness for all three regimes, activity was significantly higher on LD 12:12 h and LD 6:18 h than on the LD 18:6 h regime. 5. In order to place the experimental studies in context with the life cycle under natural conditions, pitfall traps were used to compare the seasonal activity of N. salina in the field.     

Diverse diet compositions among harpaline ground beetle species revealed by mixing model analyses of stable isotope ratios

1. Species diversities of some insect lineages have been attributed to differentiation of feeding habits among species. Our objective was to determine variation in diet composition among harpaline ground beetle species occurring in a riverside grassland. 2. We examined the diet compositions of 14 species from six genera in the spring and 10 species from two genera in the autumn. We performed measurements of nitrogen and carbon stable isotope ratios in consumers and in their potential food items, and estimated relative contributions of different food items with two mixing models, IsoSource and MixSIR. 3. IsoSource and MixSIR software gave similar results, but IsoSource tended to calculate higher contributions of principal food items and smaller percentile ranges than MixSIR. Among harparine beetle species, there were diverse food utilisation patterns among four food categories (detritivorous invertebrates, herbivorous invertebrates, C3 plants, and C4 plants). Detritivores comprised the main diets of abundant harpaline species in the spring, whereas abundant harpaline species in the autumn were primarily herbivores feeding on C4 plants, or omnivores feeding on herbivorous invertebrates and C3 plants. Seasonal changes in food use were related to seasonal changes in the abundance of each food resource. 4. Mixing model analysis of stable isotope ratios is a convenient and effective method for roughly estimating diets of many species with diverse food habits (such as ground beetles). This method can contribute to determining the trophic relationships of related insects in one ecosystem.     

Nebria brevicollis (Fabricius, 1792) in North America,benign or malign? (Coleoptera,Carabidae, Nebriini)

Nebria brevicollis (Fabricius) is one of the most frequently encountered and widely distributed carabid beetles in Europe. Until recently, the only North American records were based on two single specimens, both from the 1930's in southeastern Canada. In 2008, this species was found at thirteen different sites in five counties in northwestern Oregon. As of the end of 2010, it has been found in thirty-four different sites in ten Oregon counties, with a north-south range of ~150 km and an east-west range of ~90 km. It was also detected in 2010 in southwestern Washington (Vancouver), just north of Portland and the Columbia River.The ecological amplitude of Nebria brevicollis in Oregon rivals that of the most eurytopic native carabid species, e.g., Pterostichus algidus LeConte and Scaphinotus marginatus (Fischer von Waldheim). It has been found in highly degraded heavy industrial sites, agricultural fields, city parks, gardens, second growth woodlands, mature conifer forests, montane rock gardens, and otherwise pristine stands of old growth noble fir, with elevations ranging from essentially sea level to 1,249 meters. Climates at these locales vary from that of the Mediterranean Willamette Valley floor, where snow rarely occurs and summers are hot and dry, to the summit of the Oregon Coast Range, where deep snow may be present from November through April and summers are cool. The carabid communities in which Nebria brevicollis has been found range from those predominantly of fellow exotic species, e.g., at heavily perturbed sites, to those where it is the only exotic species, such as at the Coast Range summit.Nebria brevicollis is clearly an invasive species in that it is not restricted to anthropogenic habitats, is rapidly expanding its North American range, and can be abundant in essentially pristine settings. What is not yet clear is whether it is or will become a damaging species. Although it is already the most abundant carabid species in some settings, based upon pitfall catches, it is unknown whether this represents competitive superiority, trap vulnerability, or utilization of previously untapped or non-limiting resources. Deleterious ecological effects could include not only competition with other predators (including other carabid species) in agricultural and natural settings but also predation upon non-adult stages of threatened and endangered species of butterflies.     

Predator feeding choice on conspicuous and non-conspicuous carabid beetles: first results

Insects use various types of behaviour, chemical defences, mimetic, aposematic or cryptic appearances as anti-predatory strategies. Among insects, carabid beetles of the genus Brachinus are distasteful prey because they discharge an irritating "cloud" of quinones when threatened. These beetles live in aggregations and adopt warning (conspicuous pattern) colours and chemicals to create a template that is easily learnt by predators. Another carabid beetle, Anchomenus dorsalis, mimics the colours and cuticular profile of Brachinus and is usually found in Brachinus aggregations. In this paper we report results from laboratory observations on feeding choice of the following natural predators - Crocidura leucodon (Insectivora: Soricidae), Ocypus olens (Coleoptera: Staphylinidae) and Podarcis sicula (Reptilia: Lacertidae) - on carabid beetle species. Comparing the number of attacks of predators towards aposematic and non-aposematic prey, there was a statistically significant preference towards non-aposematic prey.     

'Bellography': Life and Contributions of Ross and Joyce Bell, two New England Naturalists

The lives and contributions of Ross and Joyce Bell are described with particular attention to studies of invertebrate natural history in the state of Vermont and carabid beetles of several groups, including the world rhysodine fauna. Their work, all done at the University of Vermont, was mainly taxonomic in nature and included aspects of the biology of the species considered. During their careers they described more than 75% of the c. 340 rhysodine species known to science. Ross Bell also wrote a number of seminal papers about the basal relationships of the Adephaga and the comparative anatomy of carabid coxal cavities. Ross and Joyce inspired several generations of students at UVM to take up advanced work in entomology and natural history.     

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

‘Carabidologists do it all’ (Niemelä 1996a) is a phrase with which most European carabidologists are familiar. Indeed, during the last half a century, professional and amateur entomologists have contributed enormously to our understanding of the basic biology of carabid beetles. The success of the field is in no small part due to regular European Carabidologists’ Meetings, which started in 1969 in Wijster, the Netherlands, with the 14th meeting again held in the Netherlands in 2009, celebrating the 40th anniversary of the first meeting and 50 years of long-term research in the Dwingelderveld. This paper offers a subjective summary of some of the major developments in carabidology since the 1960s. Taxonomy of the family Carabidae is now reasonably established, and the application of modern taxonomic tools has brought up several surprises like elsewhere in the animal kingdom. Progress has been made on the ultimate and proximate factors of seasonality and timing of reproduction, which only exceptionally show non-seasonality. Triggers can be linked to evolutionary events and plausibly explained by the “taxon cycle” theory. Fairly little is still known about certain feeding preferences, including granivory and ants, as well as unique life history strategies, such as ectoparasitism and predation on higher taxa. The study of carabids has been instrumental in developing metapopulation theory (even if it was termed differently). Dispersal is one of the areas intensively studied, and results show an intricate interaction between walking and flying as the major mechanisms. The ecological study of carabids is still hampered by some unresolved questions about sampling and data evaluation. It is recognised that knowledge is uneven, especially concerning larvae and species in tropical areas. By their abundance and wide distribution, carabid beetles can be useful in population studies, bioindication, conservation biology and landscape ecology. Indeed, 40 years of carabidological research have provided so much data and insights, that among insects - and arguably most other terrestrial organisms - carabid beetles are one of the most worthwhile model groups for biological studies.