This study focuses on the Brazilian species of the genus Purenleon Stange (Neuroptera: Myrmeleontidae). A total of five species are herein reported to Brazil: Purenleon clavatus (Navás), Purenleon fernandezi Miller & Stange (first record for Brazil), Purenleon cautus (Walker) comb. n., and two new species: Purenleon limeiraisp. n. and Purenleon rafaelisp. n. The taxonomical status of other two species was reevaluated: Formicaleo bipunctatus Navás was synonymized under P. cautus and Feinerus nebulosus Navás was revalidated and transferred to Purenleon. A key to the South American species of Purenleon is also presented.
Nine new species of the collembolan genus Salina MacGillivray from South America are described and illustrated. Two Neotropical species were recorded for the first time from Brazil: S. dedoris Mari-Mutt and S. tristani Denis. Salina was previously known to occur in three Brazilian states, and this is now updated to include 19 states with 12 recorded species. A new proposal of morphological character description and illustration, and an identification key for the celebensis group are provided. A hypothesis for the phylogenetic relationships among 34 species of Salina (about 50% of the 72 described species) allowed three main pursuits: (a) a reevaluation of Salina species groups; (b) the first explicit interpretation of how morphological characters of these springtails may have changed during the course of the diversification of the taxon; and (c) an evaluation of the historical biogeographic connections of Salina, with an emphasis on the celebensis group distribution to the New World.
The tribe Sisyphini sensu strictoMulsant, 1842 comprises only three genera, the widespread SisyphusLatreille, 1807 and NeosisyphusMüller, 1942, and the Mauritius endemic, NesosisyphusVinson, 1946. In southern Africa, Sisyphus and Neosisyphus are represented by five species groups in each genus. Together, they comprise a total of 33 valid species, of which six are new: Sisyphus auricomussp. n;Sisyphus australissp. n; Sisyphus bicuariensissp. n; Sisyphus inconspicuussp. n; Sisyphus swazisp. n; and Neosisyphus tembyisp. n. A further Southern African species, Sisyphus crispatusGory, 1833, is proposed as a nomen dubium. Sisyphus natalensisBalthasar, 1968 (syn. n), and Sisyphus bornemisszanusEndrödi, 1983 (pars) (syn. n) are made synonyms of Sisyphus sordidusBoheman, 1857. Lectotypes and paralectotypes are designated for Sisyphus costatus (Thunberg, 1818); Sisyphus seminulumGerstaecker, 1871; Sisyphus nanniscusPéringuey, 1901; Sisyphus transvaalensisPéringuey 1901; Neosisyphus spinipes (Thunberg, 1818) and Neosisyphus barbarossa (Wiedemann, 1823). Diagnoses, photographs of habitus and male genitalia, lists of examined material and distribution maps are presented for all species. An identification key to the southern African sisyphine species is provided.
The study focused on the behaviour of sit-and-wait antlion larvae in interspecific interactions. Antlion larvae usually occur in clusters with a high density of individuals; therefore, competition can be intense. We observed two abundant antlion species, E. nostras and M. formicarius, which co-occur in some habitats. In a simple habitat choice experiment where substrates differed according to sand particle size, we found that E. nostras exhibited dominance over M. formicarius. Most E. nostras larvae remained in the more suitable substrate and constructed pits, while all the M. formicarius larvae moved out of the suitable area, and did not build pits. In the second experiment, we observed the characteristics of the pit-fall traps and scored the occurrence of larval relocation in relation to interactions and in the control group, where larvae were kept in containers separately. In interactions, the larvae of E. nostras constructed smaller pits, but pit enlargement was greater in comparison to the control group. M. formicarius larvae constructed similar sized pits in both groups; however, enlargement was greater in the control group. Relocation of larvae occurred only during interactions. In direct interactions, we found 15 behavioural patterns, which are described in detail for the first time. In the presence of a competitor, larvae showed intense territorial behaviour. We recorded several behavioural patterns during larval confrontation, and interestingly, intraguild predation rarely occurred. In most cases, E. nostras larvae outcompete M. formicarius, which was evident from the larger pits and the rate of pit-construction.
Co-occurring species often compete with each other directly and indirectly. Intra-guild predation (IGP) is an extreme manifestation of direct competition, which involves the attack, killing and eating of potential competitors. We studied the competitive interactions between two pit-building antlion species that co-occur in the Israeli desert: Myrmeleon hyalinus residing in the more productive sandy soil, and Cueta lineosa solely inhabiting poorer loess soils. To understand the mechanisms driving C. lineosa away from the more productive habitat, we explored the factors triggering IGP of one antlion species on the other. We tested whether IGP is affected by soil type, depth and temperature. IGP was asymmetrical with M. hyalinus preying on C. lineosa, and it intensified as the size difference favoring the former increased. Interactive rather than additive effects governed IGP, which was lowest in sandy soil combined with low temperature, and highest in shallow loess soil. C. lineosa possesses a smaller head and thorax relative to its abdomen compared to M. hyalinus, providing a possible explanation for the advantage of M. hyalinus in direct competition. We then focused on the weaker competitor, C. lineosa, examining how it copes with competition induced by M. hyalinus. Both the growth and survival rates of C. lineosa declined in the presence of M. hyalinus. The asymmetrical IGP C. lineosa experiences from M. hyalinus combined with its competitive inferiority may explain why it is mostly found in poor habitats, while its intra-guild competitor is abundant in the more productive habitats.
Traps are rarely used by animals, despite the plausible benefits of broadening the number and diversity of prey that sit-and-wait foragers might be able to capture. The most well-known trap building sit-and-wait foragers are among the invertebrates, i.e. antlions, wormlions, glow worms, caddisflies, and spiders. A plausible hypothesis for the paucity of trap building by other animals is that biomechanical limitations render them inefficient or ineffective at catching sufficient prey. Here I examined the literature to make a valued judgement about the validity of this hypothesis. It appears that antlion and wormlion pit traps cannot catch and retain the largest prey they might expect to encounter. Arachnacampa glowworm traps are functionally efficient, facilitated by the animal’s bioluminescence. Nevertheless they only function in very moist or humid conditions. Caddisfly traps rely on flowing water to be able to capture their prey. Spiders are exceptional in developing a wide range of prey trapping strategies, from webs with dry adhesives, to sticky orb webs, to modified orb webs, e.g. elongated “ladder” webs, to webs with additional structures, and web aggregations. Some spiders have even redesigned their webs to minimize the high prey escape rates associated with web two dimensionality. These webs nevertheless are constructed and used at specific costs. While hard data across all of the invertebrate predators is lacking, there seems to be credence in the hypothesis that the biomechanical limitations placed on trap functionality can explain their limited use among animals.
Some terrestrial leeches mate by entwining the anterior ends of their bodies and then copulating. Here, we report first observations of a similar behavioral pattern in Haemadipsa picta terrestrial leeches from Malaysian Borneo. However, because the observed pattern can be easily induced artificially with no clear evidence of copulation, we suggest that it may serve another function, particularly in H. picta. We hypothesize that the wrestling behavior, as we term it, may be a ritualized aggressive display driven by competition for ambush location. Haemadipsid fauna of the region is poorly studied, therefore our observations extend limited knowledge about these leeches and open interesting research avenues for the study of the wrestling behavior.
Carnivorous plants are pure sit-and-wait predators: they remain rooted to a single location and depend on the abundance and movement of their prey to obtain nutrients required for growth and reproduction. Yet carnivorous plants exhibit phenotypically plastic responses to prey availability that parallel those of non-carnivorous plants to changes in light levels or soil-nutrient concentrations. The latter have been considered to be foraging behaviors, but the former have not. Here, I review aspects of foraging theory that can be profitably applied to carnivorous plants considered as sit-and-wait predators. A discussion of different strategies by which carnivorous plants attract, capture, kill, and digest prey, and subsequently acquire nutrients from them suggests that optimal foraging theory can be applied to carnivorous plants as easily as it has been applied to animals. Carnivorous plants can vary their production, placement, and types of traps; switch between capturing nutrients from leaf-derived traps and roots; temporarily activate traps in response to external cues; or cease trap production altogether. Future research on foraging strategies by carnivorous plants will yield new insights into the physiology and ecology of what Darwin called “the most wonderful plants in the world”. At the same time, inclusion of carnivorous plants into models of animal foraging behavior could lead to the development of a more general and taxonomically inclusive foraging theory.
The remarkable diversity of antlions in the Afrotropical region is counterbalanced by the scarce knowledge of their biology and ecology. In particular, their larval stages are largely unknown and the morphology of African pit-building species was never investigated in detail. The larvae of three pit-building species attaining a wide distribution across the whole continent, namely Myrmeleon caliginosus, M. obscurus and M. quinquemaculatus are described, illustrated and compared with congeners for the first time. Moreover, M. caliginosus is reported for the first time from Namibia, notably extending the known range of this antlion, with implications on the taxonomy and the identification of African Myrmeleon species. The larvae of these three species highlight the overall conservative morphology across the whole genus, differing in relatively minor characters such as size, proportions, pattern and chaetotaxy.