Personality affects defensive behaviour of Porcellio scaber (Isopoda,Oniscidea)

We evaluated individual behavioural patterns of isopods expressed as tonic immobility following some intrusive treatments. Common rough woodlice, Porcellio scaber, were kept individually in plastic boxes and tested for tonic immobility repeatedly. Reactivity, sensitivity (number of stimuli needed to respond), and endurance of tonic immobility (TI) according three types of treatments (touch, squeeze, drop) were evaluated. Touch was the weakest treatment and it was necessary to repeat it a number of times to obtain a response; while squeeze and drop induced TI more frequently. Nevertheless, duration of the response persisted for a longer time with the touch treatment. Within each set of the three treatment, the strongest response was the third one, regardless of treatment type. Duration of reaction was affected by the size of the woodlouse, the smallest individuals feigning death for the shortest time. Despite body size, we found a significant individual pattern of endurance of TI among tested woodlice, which was stable across treatments as well as across time (5 repetitions during a 3 week period). Porcellio scaber is one of the first species of terrestrial isopods with documented personality traits.     

Microplastic ingestion affects hydrogen production and microbiomes in the gut of the terrestrial isopod Porcellio scaber

Microplastic (MP) is an environmental burden and enters food webs via ingestion by macrofauna, including isopods (Porcellio scaber) in terrestrial ecosystems. Isopods represent ubiquitously abundant, ecologically important detritivores. However, MP-polymer specific effects on the host and its gut microbiota are unknown. We tested the hypothesis that biodegradable (polylactic acid [PLA]) and non-biodegradable (polyethylene terephthalate [PET]; polystyrene [PS]) MPs have contrasting effects on P. scaber mediated by changes of the gut microbiota. The isopod fitness after an 8-week MP-exposure was generally unaffected, although the isopods showed avoidance behaviour to PS-food. MP-polymer specific effects on gut microbes were detected, including a stimulation of microbial activity by PLA compared with MP-free controls. PLA stimulated hydrogen emission from isopod guts, while PET and PS were inhibitory. We roughly estimated 10⁷ kg year⁻¹ hydrogen emitted from the isopods globally and identified their guts as anoxic, significant mobile sources of reductant for soil microbes despite the absence of classical obligate anaerobes, likely due to Enterobacteriaceae-related fermentation activities that were stimulated by lactate generated during PLA-degradation. The findings suggest negative effects of PET and PS on gut fermentation, modulation of important isopod hydrogen emissions by MP pollution and the potential of MP to affect terrestrial food webs.     

An evolutionary timescale for terrestrial isopods and a lack of molecular support for the monophyly of Oniscidea (Crustacea: Isopoda)

The marine metazoan fauna first diversified in the early Cambrian, but terrestrial environments were not colonized until at least 100 million years later. Among the groups of organisms that successfully colonized land is the crustacean order Isopoda. Of the 10,000 described isopod species, ~ 3,600 species from the suborder Oniscidea are terrestrial. Although it is widely thought that isopods colonized land only once, some studies have failed to confirm the monophyly of Oniscidea. To infer the evolutionary relationships among isopod lineages, we conducted phylogenetic analyses of nuclear 18S and 28S and mitochondrial COI genes using maximum-likelihood and Bayesian methods. We also analyzed a second data set comprising all of the mitochondrial protein-coding genes from a smaller sample of isopod taxa. Based on our analyses using a relaxed molecular clock, we dated the origin of terrestrial isopods at 289.5 million years ago (95% credibility interval 219.6–358.9 million years ago). These predate the known fossil record of these taxa and coincide with the formation of the supercontinent Pangaea and with the diversification of vascular plants on land. Our results suggest that the terrestrial environment has been colonized more than once by isopods. The monophyly of the suborder Oniscidea was not supported in any of our analyses, conflicting with classical views based on morphology. This draws attention to the need for further work on this group of isopods.     

“Candidatus Hepatoplasma crinochetorum,” a New, Stalk-Forming Lineage of Mollicutes Colonizing the Midgut Glands of a Terrestrial Isopod

Uncultivated bacteria that densely colonize the midgut glands (hepatopancreas) of the terrestrial isopod Porcellio scaber (Crustacea: Isopoda) were identified by cloning and sequencing of their 16S rRNA genes. Phylogenetic analysis revealed that these symbionts represent a novel lineage of the Mollicutes and are only distantly related (<82% sequence identity) to members of the Mycoplasmatales and Entomoplasmatales. Fluorescence in situ hybridization with a specific oligonucleotide probe confirmed that the amplified 16S rRNA gene sequences indeed originated from a homogeneous population of symbionts intimately associated with the epithelial surface of the hepatopancreas. The same probe also detected morphotypically identical symbionts in other crinochete isopods. Scanning and transmission electron microscopy revealed uniform spherical bacterial cells without a cell wall, sometimes interacting with the microvilli of the brush border by means of stalk-like cytoplasmic appendages, which also appeared to be involved in cell division through budding. Based on the isolated phylogenetic position and unique cytological properties, the provisional name “Candidatus Hepatoplasma crinochetorum” is proposed for this new taxon of Mollicutes colonizing the hepatopancreas of P. scaber.     

Pathogenic effect of entomopathogenic nematode-bacterium complexes on terrestrial isopods

In this study, we evaluated the effect of entomopathogenic nematodes (EPNs) Steinernema carpocapsae, Steinernema feltiae and Heterorhabditis bacteriophora, symbiotically associated with bacteria of the genera Xenorhabdus or Photorhabdus, on the survival of eight terrestrial isopod species. The EPN species S. carpocapsae and H. bacteriophora reduced the survival of six isopod species while S. feltiae reduced survival for two species. Two terrestrial isopod species tested (Armadillidium vulgare and Armadillo officinalis) were found not to be affected by treatment with EPNs while the six other isopod species showed survival reduction with at least one EPN species. By using aposymbiotic S. carpocapsae (i.e. without Xenorhabdus symbionts), we showed that nematodes can be isopod pathogens on their own. Nevertheless, symbiotic nematodes were more pathogenic for isopods than aposymbiotic ones showing that bacteria acted synergistically with their nematodes to kill isopods. By direct injection of entomopathogenic bacteria into isopod hemolymph, we showed that bacteria had a pathogenic effect on terrestrial isopods even if they appeared unable to multiply within isopod hemolymphs. A developmental study of EPNs in isopods showed that two of them (S. carpocapsae and H. bacteriophora) were able to develop while S. feltiae could not. No EPN species were able to produce offspring emerging from isopods. We conclude that EPN and their bacteria can be pathogens for terrestrial isopods but that such hosts represent a reproductive dead-end for them. Thus, terrestrial isopods appear not to be alternative hosts for EPN populations maintained in the absence of insects.     

Marsupium morphology and brooding biology of the Antarctic giant isopod,Glyptonotus antarcticus Eights 1853 (Crustacea,Isopoda, Chaetiliidae)

The marsupium of the Antarctic giant isopod, Glyptonotus antarcticus Eights 1853, has unique characteristics. It deviates in its proportions and construction from the so called Idotea type of brood pouch found in other marine isopod species; some features even remind you of the so called Porcellio type of marsupium which is typical of terrestrial isopods. Details are described by scanning electron microscopy. From our observations and from reviewed data, we suggest that, during the prolonged incubation of brood, adelphophagy contributes to the nourishment of the developing young, and assume that additional nutrition is provided by maternal secretion. These suggestions would partly explain marsupial conditions in G. antarcticus as an adaptation to slow development in an adverse environment. Two species of epizoa, a turbellarian and a fish leech, were found to occur on G. anarcticus in the vicinity of the marsupium.Contribution No. 561 of the Alfred-Wegener-Institute of Polar and Marine Research (AWI Bremerhaven)     

Thaumamermis cosgrovei n. gen., n. sp. (Mermithidae: Nematoda) parasitizing terrestrial isopods (Isopoda: Oniscoidea)

Summary A new mermithid nematode, Thaumamermis cosgrovei n. gen., n. sp. (Mermithidae: Nematoda) was found parasitizing two terrestrial isopods (Isopoda: Oniscoidea) in California. The hosts, Armadillidium vulgare (Latr.) (a pillbug) and Porcellio scaber (Latr.) (a sowbug) represent the first cases of isopods attacked by mermithid nematodes. The genus Thaumamermis can be distinguished from all previously described mermithids by the extremely dimorphic spicules, one being short and broad and the other long and filiform. It has been discovered that the nematodes are infected with an iridiovirus which commonly destroys the isopod hosts. ac]19800917     

Occurrence and assemblage composition of millipedes (Myriapoda, Diplopoda) and terrestrial isopods (Crustacea, Isopoda, Oniscidea) in urban areas of Switzerland

Terrestrial isopods and millipedes, members of the invertebrate macro-decomposer guild, were collected through pitfall traps in three Swiss cities (Zurich, Lucerne, Lugano). A total of 7,198 individuals of 17 isopod species (7093 ind.), and 10 millipede species (105 ind.) were captured. Besides the Alpine endemic isopod (Trichoniscus alemannicus) and millipede (Cylindroiulus verhoeffi), urban assemblages were mainly composed of widespread, native European and even cosmopolitan species, which are frequent in anthropogenic areas. Overall species richness (isopods and millipedes combined) was similar in Zurich (17 species) and Lucerne (16), while only 13 species were sampled in Lugano. According to the Sørensen index of similarity, species composition of Zurich and Lucerne were more alike, while the one of Lugano was more distinct from the other two cities. This result can be explained by the spatial proximity of Zurich and Lucerne in the north of the Alps compared to Lugano, which is located more distantly and in the south of the Alps. Dominant isopods and millipedes in Zurich and Lucerne were found to be widespread synanthropic species in temperate Europe(Porcellio scaber, Trachelipus rathkii and Ophyiulus pilosus) while the dominant isopod in Lugano (Trachelipus razzautii) is a species with a north-eastern Mediterranean distribution. Our study reveals that the urban millipede and isopod fauna in Swiss cities mainly consists of widespread species, but species of narrower distribution (e.g. Trichoniscus alemannicus, Cylindroiulus verhoeffi) may also find suitable habitats in cities. Despite some signs of biotic homogenization, our study also found compositional differences of millipede and isopod assemblages between northern and southern cities that suggest geographical effects of the regional species pool.     

Granivory in terrestrial isopods

Abstract Granivory (seed feeding) evolved in many animal groups. Field observations hint at the existence of granivory in terrestrial isopods (Crustacea: Isopoda: Oniscidea), for which it was previously unknown. In this paper granivory in terrestrial isopods is addressed for the first time, focusing on (i) seed acceptance in the presence of plant litter and (ii) size as a constraint for acceptance and consumption. In a laboratory choice experiment, Armadillidium vulgare consumed seeds of Capsella bursa‐pastoris and Poa annua when plant litter was present. In a no‐choice experiment, seeds of seven plant species were offered to four isopod species giving 13 combinations in total [A. vulgare (seven species of seeds), Oniscus asellus (two), Porcellio scaber (two), and Porcellionides pruinosus (two)]. The tested isopods differed in their acceptance (proportion of individuals consuming seeds) and consumption (both number and amount of seeds eaten) of seed species. Size as a constraint was demonstrated in A. vulgare offered Cirsium arvense seed, since the probability that this large seed was eaten increased with body size of the isopod. In the other 10 seed–isopod pairs, seed consumption increased linearly with isopod body size. Granivory is thus widespread in terrestrial isopods, although the tendency to eat seeds differs between species.     

Laboratory infection of terrestrial isopods (Crustacea: Isopoda) with neoaplectanid and heterorhabditid nematodes (Rhabditida: Nematoda)

Under laboratory conditions, the nematodes Neoaplectana carpocapsae and Heterorhabditis heliothidis were able to infect and develop inside the hemocoel of terrestrial isopods belonging to the genus Porcellio. Armidillidium vulgare was also infected by N. carpocapsae, but this host was less susceptible than Porcellio. Results show that, under suitable ecological conditions, it would be feasible to utilize N. carpocapsae as a biological control agent of sowbugs (Porcellio spp.). This is the first report showing the ability of neoaplectanids and heterorhabditids to invade representatives of the Crustacea.     

The influence of habitat heterogeneity on host-pathogen population dynamics

The influence of spatial heterogeneity on the population dynamics of a naturally occurring invertebrate host-pathogen system was experimentally investigated. At ten week intervals over a two year period, I quantified the spatial distribution of natural populations of the terrestrial isopod crustacean Porcellio scaber infected with the isopod iridescent virus (IIV). During the seasonally dry periods of summer and early fall in central California, isopod populations were highly aggregated and the degree of patchiness and distance between inhabited patches was greatest. Coincident with increased patchiness and patch spacing was an increase in isopod density within patches. During the wet seasons of winter and spring, isopod population patchiness, inter-patch spacing, and within-patch density was low. Seasonal changes in virus prevalence were negatively correlated with within-patch density, patchiness, and inter-patch spacing. The influence of the spatial distribution of isopods on virus prevalence was also tested in field experiments. The virus was introduced into arrays of artificial habitat patches colonized by isopods in which interpatch distance was varied. The prevalence of resulting infections was monitored at weekly intervals. In addition, dispersal rates between artificial patches and natural patches were quantified and compared. The results showed that isopods in treatments with the smallest inter-patch spacing had the highest virus prevalence, with generally lower prevalence among isopods in more widely spaced patches. The spacing of experimental patches significantly affected virus prevalence, although the experiments did not resolve a clear relationship between patch spacing and virus prevalence. Rates of dispersal between patches decreased with increased patch spacing, and these rates did not differ significantly from dispersal between natural patches. The results suggest that rates of dispersal between isopod subpopulations may be an important component of the infection dynamics in this system. I discuss the consequences of these findings for host-pathogen dynamics in fragmented habitats, and for other ecological interactions in spatially heterogeneous habitats.     

Holcus lanatus invasion slows decomposition through its interaction with a macroinvertebrate detritivore, Porcellio scaber

Detritus based food webs may mediate the impacts of invasive species on ecosystem processes. Holcus lanatus (L.) is an invasive perennial grass that is rapidly spreading in the coastal prairie of California. We used litterbags to determine if H. lanatus altered the rate of litter decomposition through its interaction with the dominant macroinvertebrate detritivore at our study site, the isopod Porcellio scaber (Latreille). Over the course of a year, H. lanatus litter loss was 15% less than annual grasses, a difference that was directly attributable to P. scaber. Although there was no effect of isopods on litter loss during the winter, when most decomposition occurred, isopods had substantial effects on litter loss of annual grasses during the summer. P. scaber had no effect on litter loss of H. lanatus litter. Our findings suggest that H. lanatus invasion slows decomposition in the coastal prairie because it is unusually refractory to an important detritivore. The decreased decomposition of H. lanatus litter, along with increased production during the growing season, lead to a doubling of the end-of-season litter biomass where H. lanatus had invaded.     

Metabolic adaptations for isopod specialization in three species of Dysdera spiders from the Canary Islands

The spider genus Dysdera is considered to comprise specialist isopod feeders, although the degree of specialization varies between species, depending on morphological (shape of chelicerae), behavioural (attack tactics) and metabolic (food quality of prey) adaptations. Dysdera has radiated extensively in the Canary Islands (currently 47 endemic species are described) and codistributed species have different cheliceral shapes and body sizes indicating different feeding niches. In the present study, we investigate the existence of metabolic adaptations to feeding on isopods by three endemic species (Dysdera insulana Simon, Dysdera macra Simon and Dysdera verneaui Simon) from Tenerife. We hypothesize that there is enhanced extraction efficiency of fundamental macronutrients from isopods compared with control prey in species with special morphological and behavioural adaptations for this prey type. We measure quantitatively spider growth, dry mass consumption, lipid and nitrogen consumption, and calculate growth efficiency and efficiency of utilization of dry mass, lipid and nitrogen. The results show that all three species are able to utilize both prey types, indicating that none of them are strict isopod specialist. Dysdera insulana shows enhanced growth efficiency and D. macra shows enhanced nitrogen extraction efficiency compared with D. verneaui when feeding on Porcellio rather than on Musca. Both traits indicate likely adaptations for the utilization of isopods. Spider species, sex and prey type all affect lipid and nitrogen extraction efficiencies, indicating that spiders do not simply extract nutrients in the proportions available. The results support the hypothesis that adaptations for enhanced digestion of focal prey evolve in species that already have adaptations for enhanced capture success.     

A terrestrial micro-ecosystem for measuring effects of pollutants on isopod-mediated litter decomposition

Soil fauna-mediated litter decomposition was simulated in micro-ecosystems, using oak and poplar litter, with the isopod Porcellio scaber (Crustacea) as a representative soil fauna species. The aim was to identify the conditions under which decomposition rate and influence of isopods could be established accurately, yet keeping the system complex enough to be relevant for the field situation. The results showed that it was possible to divide total carbon dioxide production of a micro-ecosystem into three components: microbial respiration, isopod respiration and extra microbial, isopod-mediated respiration. The isopods stimulated the microbial respiration by 10–50%, depending on litter type and experimental design. It appears that this stimulation is achieved in two ways: 1. by increasing litter moisture content and 2. by production of faecal pellets. It is concluded that the micro-ecosystem described in this paper combines ecological relevance with reproducibility and simplicity of operation and thus provides a useful tool for measuring effects of soil contaminants.     

Does temperature and oxygen affect duration of intramarsupial development and juvenile growth in the terrestrial isopod Porcellio scaber (Crustacea,Malacostraca)?

According to the temperature-size rule (TSR), ectotherms developing under cold conditions experience slower growth as juveniles but reach a larger size at maturity. Whether temperature alone causes this phenomenon is unknown, but oxygen limitation can play a role in the temperature-size relationship. Oxygen may become limited under warm conditions when the resulting higher metabolism creates a greater demand for oxygen, especially in larger individuals. We examined the independent effects of oxygen concentration (10% and 22% O₂) and temperature (15 °C and 22 °C) on duration of ontogenic development, which takes place within the maternal brood pouch (marsupium), and juvenile growth in the terrestrial isopod common rough woodlouse (Porcellio scaber). Individuals inside the marsupium undergo the change from the aqueous to the gaseous environment. Under hypoxia, woodlice hatched from the marsupium sooner, but their subsequent growth was not affected by the level of oxygen. Marsupial development and juvenile growth were almost three times slower at low temperature, and marsupial development was longer in larger females but only in the cold treatment. These results show that temperature and oxygen are important ecological factors affecting developmental time and that the strength of the effect likely depends on the availability of oxygen in the environment.     

Formation of the hindgut cuticular lining during embryonic development of Porcellio scaber (Crustacea,Isopoda)

The hindgut and foregut in terrestrial isopod crustaceans are ectodermal parts of the digestive system and are lined by cuticle, an apical extracellular matrix secreted by epithelial cells. Morphogenesis of the digestive system was reported in previous studies, but differentiation of the gut cuticle was not followed in detail. This study is focused on ultrastructural analyses of hindgut apical matrices and cuticle in selected intramarsupial developmental stages of the terrestrial isopod Porcellio scaber in comparison to adult animals to obtain data on the hindgut cuticular lining differentiation. Our results show that in late embryos of stages 16 and 18 the apical matrix in the hindgut consists of loose material overlaid by a thin intensely ruffled electron dense lamina facing the lumen. The ultrastructural resemblance to the embryonic epidermal matrices described in several arthropods suggests a common principle in chitinous matrix differentiation. The hindgut matrix in the prehatching embryo of stage 19 shows characteristics of the hindgut cuticle, specifically alignment to the apical epithelial surface and a prominent electron dense layer of epicuticle. In the preceding embryonic stage – stage 18 – an electron dense lamina, closely apposed to the apical cell membrane, is evident and is considered as the first epicuticle formation. In marsupial mancae the advanced features of the hindgut cuticle and epithelium are evident: a more prominent epicuticular layer, formation of cuticular spines and an extensive apical labyrinth. In comparison to the hindgut cuticle of adults, the hindgut cuticle of marsupial manca and in particular the electron dense epicuticular layer are much thinner and the difference between cuticle architecture in the anterior chamber and in the papillate region is not yet distinguishable. Differences from the hindgut cuticle in adults imply not fully developed structure and function of the hindgut cuticle in marsupial manca, possibly related also to different environments, as mancae develop in marsupial fluid. Bacteria, evenly distributed within the homogenous electron dense material in the hindgut lumen, were observed only in one specimen of early marsupial manca. The morphological features of gut cuticle renewal are evident in the late marsupial mancae, and are similar to those observed in the exoskeleton.     

A cryofixation study of presumptive hygroreceptors on the antennule of a terrestrial isopod

The structure of the apical sensilla on the antennule of the terrestrial isopod Porcellio scaber was examined in cryofixed and freeze substituted (CRF) and chemically fixed and dehydrated (CHF) material. CRF specimens generally showed a preservation superior to CHF material. Only in deeper regions did the tissue show damage from freezing. Each of the 13–22 sensilla contains two sensory cells. In contrast to earlier reports, it was observed that the dendritic segments of these cells are arranged in a unique, concentric manner. In CRF specimens the dendrites reach the tip of the sensilla and border upon the innermost layer of the complicated wall of the peg which is not pierced by pores. Silver-protein and lanthanum failed to penetrate the wall of the sensilla and also did not reach the dendrites via an apical pore, which therefore is regarded as a molting pore. The lymph spaces which, in CHF specimens, are observed around the dendrites and beneath the cuticle within the antennal tip are regarded as artefactual. From similarities in the dendritic structures to insect hygroreceptors and their relationship to the adjoining cuticle it can be assumed that the antennular sensilla in Porcellio are sensitive to humidity changes. Mechanoreception and chemoreception, however, cannot entirely be excluded as possible functions.     

Body shape in terrestrial isopods: A morphological mechanism to resist desiccation?

Woodlice are fully terrestrial crustaceans and are known to be sensitive to water loss. Their half‐ellipsoidal shapes represent simple models in which to investigate theoretical assumptions about organism morphology and rates of exchange with the environment. We examine the influence of surface area and mass on the desiccation rates in three eco‐morphologically different species of woodlice: Oniscus asellus, Porcellio scaber, and Armadillidium vulgare. Our analysis indicates that the rate of water loss of an individual depends on both the initial weight and the body surface area. Interspecific and intraspecific analyses show that the mass‐specific water loss rate of a species decreases along with the ratio of surface area to volume. In particular, we show that body shape explains the difference in mass‐specific water loss rates between A. vulgare and P. scaber. This observation also explains several known ecological patterns, for example, the distribution and survivorship of individuals. However, in addition to body size and shape, water loss in terrestrial isopods depends also on the coefficient of permeability (i.e., a measure of water loss rate per surface unit), which is high in O. asellus and lower (and at similar levels) in P. scaber and A. vulgare. We discuss morphological, physiological, and behavioral aspects of water loss avoidance in terrestrial isopods. J. Morphol. 276:1283–1289, 2015. © 2015 Wiley Periodicals, Inc.     

Evolutionary transition to XY sex chromosomes associated with Y-linked duplication of a male hormone gene in a terrestrial isopod

Sex chromosomes are highly variable in some taxonomic groups, but the evolutionary mechanisms underlying this diversity are not well understood. In terrestrial isopod crustaceans, evolutionary turnovers in sex chromosomes are frequent, possibly caused by Wolbachia, a vertically-transmitted endosymbiont causing male-to-female sex reversal. Here, we use surgical manipulations and genetic crosses, plus genome sequencing, to examine sex chromosomes in the terrestrial isopod Trachelipus rathkei. Although an earlier cytogenetics study suggested a ZZ/ZW sex chromosome system in this species, we surprisingly find multiple lines of evidence that in our study population, sex is determined by an XX/XY system. Consistent with a recent evolutionary origin for this XX/XY system, the putative male-specific region of the genome is small. The genome shows evidence of Y-linked duplications of the gene encoding the androgenic gland hormone, a major component of male sexual differentiation in isopods. Our analyses also uncover sequences horizontally acquired from past Wolbachia infections, consistent with the hypothesis that Wolbachia may have interfered with the evolution of sex determination in T. rathkei. Overall, these results provide evidence for the co-occurrence of multiple sex chromosome systems within T. rathkei, further highlighting the relevance of terrestrial isopods as models for the study of sex chromosome evolution.Subject terms: Evolutionary genetics, Genome evolution     

Predatory Versatility in Females of the Scorpion <Emphasis Type="Italic">Bothriurus bonariensis</Emphasis> (Scorpiones: Bothriuridae): Overcoming Prey with Different Defensive Mechanisms

Scorpions are dominant predators in some environments. Nevertheless, most studies of predatory behavior in scorpions have focused on diet composition whereas some other relevant aspects, such as predatory strategy, have been poorly explored. Herein we evaluate the prey acceptance and predatory strategy of the scorpion Bothriurus bonariensis against sympatric prey with different defenses. As prey, we selected earwigs (Forficula cf. auricularia) which use pincer-like defensive appendages, hard-bodied isopods (Armadillium vulgare) known for their conglobation defensive strategy, soft bodied isopods (Porcellio cf. scaber), which secrete noxious substances as defense mechanisms, cockroaches with limited defensive mechanisms (Blatta cf. orientalis.) and spiders (Lycosa cf. poliostoma) which possess venomous fangs. Prey were offered to 21 adults of B. bonariensis in random order until all prey had been offered to all scorpions. Prey consumption and the number of attempts needed for capture were recorded. We also evaluated the effect of sting use on immobilization time as well as the prey capture strategies on the most consumed prey. We found that despite using a similar number of attempts for capturing all prey, spiders and armadillid isopods were less consumed than other prey. Immobilization times were longer for earwigs than for armadillid isopods and cockroaches. Scorpions used alternative predatory strategies against these aforementioned prey, although the stinger was used against all of them. These results show that scorpions are able to use different predatory strategies which might allow them to include prey with diverse defensive strategies in their diet.