Blaptica Dubia Research Articles

Theoretical justification for the layout of an industrial complex for the content of Blaptica dubia for the purpose of obtaining feed and food products

It is predicted that by 2050, up to 15% of proteins will be produced by insects [1; 6; 7]. Fats and enzymes, as well as chitinous coatings, ingredients currently widely used in cosmetology and the chemical industry, are valuable by-products [3]. The advantages of enterprises aimed at using insects as productive animals are lower expenditure on feed, insects have a more flexible digestive system and highly active enzymes, which allows them to obtain maximum energy and nutrients even from not the highest quality feed [5]. The Argentine cockroach is superior to other productive insects in many respects, which may make it the most promising species for the development of industrial entomology.

Classification, identification, and DNA barcoding study for common cockroach species (Dictyoptera: Blattaria) from China

Cockroaches are well-known pests and quarantined organisms worldwide. Due to morphological diversity and a lack of molecular data, their classification and identification are facing challenges. This study performed classification, identification, and DNA barcoding for cockroaches collected from China. Seventy-six samples were morphologically identified as seven species of two superfamilies that included Blattella germanica, Eublaberus posticus and Blaptica dubia belonging to the superfamily Blaberoidea, and Periplaneta americana, Periplaneta lateralis, Periplaneta fuliginosa and Periplaneta australasiae belonging to the superfamily Blattoidea. Based on sequence alignments of nine ribosomal and mitochondrial genes across the order Blattaria retrieved from GenBank, rDNA ITS2-517 bp and mtDNA 16S-327 bp were screened as candidates for molecular identification. Universal primers were designed for PCR amplification, cloning, and sequencing of the 37 representative samples. Sequence alignments and phylogeny analysis showed that both ITS2 and 16S confirmed samples 1–9, 20–24, and 25–29 as B. germanica, P. americana, and P. lateralis, respectively; only 16S (not ITS2) confirmed samples 10–14, 15–19, 30–34, and 35–37 as E. posticus, Blap. dubia, P. fuliginosa, and P. australasiae, respectively, indicating that 16S was a better target than ITS2 for molecular identification of cockroaches. Conservative motif and divergence analysis further revealed that ITS2 sequences vary significantly among different taxa, whereas 16S sequences are relatively conserved. There is an obvious barcoding gap between maximum intraspecific divergence and minimum interspecific divergence (2.57 % vs. 5.62 %) for ITS2, but not for 16S (6.15 % vs. 2.63 %). Therefore, it was confirmed that ITS2 is an ideal DNA barcode for molecular identification of cockroaches at lower category.

Conspecific and heterospecific cueing in shelter choices of Blaptica dubia cockroaches.

Like many cockroaches, Argentinian wood roaches, Blaptica dubia, prefer darker shelters over lighter shelters. In three experiments, we asked whether chemical cues from other roaches might influence shelter choice, a process known as conspecific or heterospecific cueing, depending on whether the cues come from an individual of the same or a different species, respectively. Each experiment involved trials with focal B. dubia cockroaches in testing arenas containing plastic shelters of varying levels of darkness, with filter paper under each shelter acting as a carrier for chemical cues. In Experiment 1, we tested female and male B. dubia cockroaches with two shelters matched for darkness but differing in cues (conspecific vs. none). The shelter with no cue contained a blank filter paper as a control. In Experiment 2 (conspecific cueing) and Experiment 3 (heterospecific cueing), we tested B. dubia cockroach choices for lighter or darker shelters with filter papers containing chemical cues of other roaches or no chemical cues. For the conspecific cueing study of Experiment 2, we used chemical cues from other B. dubia cockroaches. In contrast, for the heterospecific cueing study of Experiment 3, we used chemical cues from a different species, the death's head cockroach, Blaberus craniifer. In Experiment 1, B. dubia cockroaches overwhelmingly preferred shelters with conspecific chemical cues over darkness-matched shelters without cues. In Experiments 2 and 3, they strongly preferred darker shelters, especially when chemical cues were present. Additionally, they were more likely to be under the lighter shelter when chemical cues were present there. These results reveal that the public information B. dubia cockroaches gain from chemical cues-including those from other species-can drive shelter choices in this species.

Growth Performance of Silver Arowana Fed with Gryllus mitratus (Local Cricket) and Blaptica Dubia (Dubia Roach)

This research aimed to determine the feed types for Brazilian silver Arowana (Osteoglossum bicirrhosum), consisting of Poecilia reticulata (guppy fish), Gryllus mitratus (local cricket) and Blaptica Dubia (Dubia roach). The best feed ratios were compared to improve the performance growth of Arowana. The research was conducted in October - November 2022 at the ornamental fish farm named Badai Arwana Tasikmalaya, West Java. This research used an experimental method with a completely randomized design through five treatments and four repetitions. The treatments consisted of (A) guppy fish as the control feed (100%); (B) local cricket as the tested feed (100%); (C) Dubia roach as the tested feed (100%), (D) combination of guppy fish (50%) with local cricket (50%); and (E) combination of guppy fish (50%) with Dubia roach (50%). The treatments were given for 40 days, and the growth parameters of those Arowana seeds were then observed every 10 days. The observed parameters covered Survival Rate (SR), Absolute Length Growth (L), Absolute Weight Growth (W), Feed Conversion ratio (FCR), and Water Quality. SR, W, L, and FCR data were analyzed using ANOVA with a significant level of 95% and if there is a significant difference, the Duncan test will be further conducted. Meanwhile, water quality was descriptively analyzed.
 The research results showed that the feed combination of guppy fish (50%) with local cricket (50%) could improve the SR and growth performance of Arowana seeds. The given feed combination with the ratio of guppy fish (50%) with local cricket (50%) resulted in SR (100%), L (9.07 cm), W (10.53 g), and FCR (2.36). Meanwhile, the water quality during the research was in appropriate and stable conditions.

Fatty Acid and Amino Acid Profiles of Seven Edible Insects: Focus on Lipid Class Composition and Protein Conversion Factors.

This study is based on the fatty acid and amino acid profiles of seven edible insect species: Acheta domesticus, Alphitobius diaperinus, Blaptica dubia, Galleria mellonella, Locusta migratoria, Tenebrio molitor, and Zophobas morio. The aim of the present study is to provide new data on the fatty acid distributions among lipid classes as well as the species-specific protein conversion factor (Kp) of a wide range of insects in order to further improve the nutritional characterisation of insects as food. Oleic acid was the predominant fatty acid in all insects except for A. domesticus, in which a significantly higher percentage of linoleic acid was found. The majority of the lipids were neutral lipids. A significant amount of α-linolenic acid in the phospholipid fraction of L. migratoria was shown, while in T. molitor, phospholipids were the only fraction in which a measurable amount of docosahexaenoic acid was found. Overall, in most insects, the phospholipid fraction had the highest polyunsaturated fatty acid content compared to the other classes, which may be protective in terms of auto-oxidative stability. Kp values in the range of 4.17 to 6.43 were obtained. Within the nutritional quality indices, all insects showed healthy fatty acids and high-quality amino acid profiles.

Investigation of euthanasia techniques in four species of cockroaches

While cockroaches are commonly exhibited in zoos and museums, studied in research laboratories, and even kept as pets, scientifically based guidelines for their euthanasia are lacking. This study assessed euthanasia techniques in four species of cockroaches (Dubia (Blaptica dubia), red runner (Shelfordella lateralis), Madagascar hissing (Gromphadorhina portentosa), and giant cave (Blaberus giganteus)). In an initial pilot study, two hundred fifty adult Dubia cockroaches were exposed in groups of ten to a cotton ball soaked with 2 mL of isoflurane in a 1 L air-tight chamber. Thirty minutes beyond loss of any individual movement, groups were exposed to one of the following secondary treatments: freezing at −18 °C or −80 °C from 0.25 to 24 hours; immersion in 10% neutral buffered formalin, 70% isopropyl alcohol, or reverse osmosis water for 0.25 or 0.5 hours; or intracoelomic injection of potassium chloride (456 mEq/kg) or pentobarbital-based euthanasia solution (3.9 g/kg). A control group remained in the air-tight isoflurane chamber for 24 hours. Following all treatments, cockroaches were monitored for an additional 24 hours for spontaneous movement. Irreversible loss of movement was considered synonymous with irreversible loss of consciousness (death). Across all species, isoflurane anesthesia followed by either 70% isopropyl alcohol immersion for 0.25 or 0.5 hours or isoflurane exposure for 24 hours resulted in euthanasia in 100% of cockroaches. This study is the first evaluation of American Veterinary Medical Association-recommended euthanasia protocols in cockroaches.

Influence of group size on shelter choice in Blaptica dubia cockroaches.

Individuals in social groups can gain benefits from being in those groups, including an increased ability to find food and avoid predators. We tested for potential group benefits in shelter choice in the Argentinian wood roach, Blaptica dubia. Roaches were tested in arenas with two shelters available in which one shelter was significantly darker than the other. Female and male roaches, housed separately, were tested as solitary individuals, or in same-sex groups of 5, 10, or 15. The roaches were tested under two light regimes (lights on vs. lights off) and two shelter distances (shelters near vs. shelters far) to provide variation in shelter search conditions. Solitary individuals chose the darker shelter at chance levels, but the roaches in groups chose the darker shelter significantly more often than chance. Furthermore, the two largest groups chose the darker shelter more often than the group of five roaches. We detected effects related to light variation that indicated roaches were more likely to be under either shelter in the lights-on conditions, and more likely to be out in the arena and under no shelter in the lights-off condition. Shelter distances had negligible effects on shelter choice and sex had no effect. Taken together, our results indicate individuals can make more optimal choices regarding shelter darkness if they are in a group, and that decision-making related to shelter is sensitive to variation in social context. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

MORPHOLOGICAL AND QUANTITATIVE STUDIES OF THE HEMOCYTES IN NYMPH AND IMAGO OF BLAPTICA DUBIA (SERVILLE, 1839)

The purpose of the research is to analyze how the hemocyte counts and their morphological characteristics change during development of Blaptica dubia, especially during molting. And to suggest a possible scheme of the transformation of spherulocytes into crescent-cells.
 Materials and methods. Quantitative and morphological features of hemocytes of imago and nymphs of 1-4 stages of Blaptica dubia using light microscopy and AFM were researched. Cell, nucleus and granule sizes were determined using NIS-Elements and NOVA software. Cytochemical tests with neutral red and alcyan blue allowed us to identify different cell types.
 Results. This study presents a classification of hemocytes in Blaptica dubia, that based on morphological and cytochemical characteristics of cells. We analyzed the dynamics of the hemocytes counts in 6 nymphs (1-4 stages) and 6 imago. Special attention is given to the moment of molting. Seven hemocyte types were described and identified as: prohemocytes, plasmocytes, granulocytes, vermicytes, spherulocytes, coagulocytes and crescent-cells. The stem cells (prohemocytes) and spherulocytes were the predominant hemocytes. Prohemocytes counts decrease as a result of insect development, instead the relative number of plasmocytes and granulocytes increases. Spherulocytes counts could increase to 35% at the moment of leaving the ootheca and at the molting period. Due to the study of hemocytes diversity in different nymph stages, interim cells and possible ways of their transformations were identified. The unusual crescent-cells, that were unique for Gromphadorhina portentosa, had been found in Blaptica dubia. For the first time, the cytochemical test allowed to determine the origin of crescent-cells from spherulocytes.

DNA Barcoding of Commercial Cockroaches in Turkey

Accurate species identification has become a precondition for accomplished biodiversity administration and further genetic research. Species acquaintance technics require molecular tools such as DNA barcoding as well as morphological identification for accurate identification. Particularly, the application of subunit I of the mitochondrial cytochrome c oxidase (COI) gene for DNA barcoding for insects has approved to be very useful in species acquaintance. The main aim of this study is to generate the first reference library of DNA barcode for cockroaches in Turkey using previously published data. As a result of the literature research, it has been observed that no study has been carried out on the DNA barcode of Turkish cockroaches. Therefore, in this study, we evaluated the advantage of DNA barcoding applied to two cockroach samples from Turkey for the first time. Our working samples implicated 10 DNA barcodes grounded on sequences created from our present study and 109 other DNA barcodes from BOLD. Various molecular analyzes including genetic distance-origin assessment (NeighborJoining and Maximum Likelihood trees) has been applied to accurately identify and describe species. In addition, Blaptica dubia (B. dubia) (Serville, 1838) and Nauphoeta cinerea (N. cinerea) (Olivier, 1789) have been reported as the first country records. It has been observed that reference libraries like BOLD are not yet sufficiently populated with COI sequences of Turkish cockroach species. In order for Turkish cockroach bio-assessment and biodiversity studies to benefit from the advantages of DNA barcoding, it is of great importance that cockroach inventories and taxonomic studies include DNA barcodes.

Blatticomposting of Food Waste, Production Estimates, Chemical Composition and CO2 Emissions Savings: A Case Study

Half of the organic waste generated by mankind is compostable. Many of the traditional methods of food waste treatment generate pernicious effects on ecosystems, such as leachates, greenhouse gases, pathogenic microorganisms or odors. Three cockroach species that are widespread as live food for feeding exotic animals (mainly reptiles) due to their high growth rates, waste consumption, production and quality of blatticompost: the Madagascar hissing cockroach (Aeluropoda insignis Butler), the Guyana spotted cockroach (Blaptica dubia Serville) and the ivory cockroach (Eublaberus sp.) has been evaluated. Neither the weight–length ratios (W–L) nor the body condition index (Krel) of the three species studied were statistically different between the control and organic waste treatment groups. Average intakes per animal per day were 0.93 g in Aeluropoda, 2.22 g in Blaptica and 2.58 g in Eublaberus. Blatticompost production rates were 0.11, 0.75 and 0.52 g / animal*day, respectively. Taking into account the differences in size and density of individuals, this implies an average waste consumption of 1015.9 g/m2*day, of which 26.7% would be transformed into blatticompost considering the three species together. This is equivalent to 304.8 mt/ha*month of food waste recycled, a blatticompost production of 81.4 mt/ha*month and an estimated greenhouse gas emission savings of 817.2 mt/ha*month. Results indicate that any of the three species studied would be a viable alternative, although the ivory cockroach (Eublaberus sp.) presents ideal characteristics. The massive use of this species in the large-scale treatment of organic waste is proposed. Given the enormous advantages of this treatment and the zero environmental costs (absence of invasive character) could be necessary to adapt the legislation of the European Community to include blatticomposting as a suitable waste treatment as it is done in other parts of the world.Graphical

The Effect of Pyrantel Pamoate Treatment on Fecal Pinworm (Leidynema appendiculata) Parasites of Dietary Dubia Roaches (Blaptica dubia): Efforts to Eliminate Passthrough Fecal Pseudoparasites in Lesser Hedgehog Tenrecs (Echinops telfairi)

Pinworm ova were discovered on lesser hedgehog tenrec (Echinops telfairi) fecal exams. Ova were passthrough pseudoparasite pinworms originating from feeder roaches (Blaptica dubia). Roaches were maintained as a feeder colony and offered to tenrecs as a portion of their diet. Pinworms were identified as Leidynema appendiculata. This study aimed to determine if these pinworms could be eliminated from the roaches. Roaches were randomly assigned into groups (n = 24), including a control (A) and four treatment groups (B–E). Treatment group roaches received oral dosing of anthelmintic pyrantel pamoate at four concentrations (mg/g as offered): 3.5 (Group B), 14.0 (Group C), 26.0 (Group D), and 35.0 (Group E). Roach diets were made weekly and offered to roaches 2 consecutive days per week for 3 consecutive weeks. The total pinworm ova per gram of roach feces examined were visually reduced in all treatment groups compared to controls at the end of the feed dosing period (Day 23). Post-treatment pinworm numbers were visually reduced in all treatment groups compared to controls on Day 29 and Day 65. Groups receiving higher concentrations of the oral dosing (C–E) significantly differed from controls at Day 29 (p = 0.0086, p = 0.0045, and p = 0.0013, respectively) with a concentration-dependent response. Parasites were not eliminated in any group at Day 29 or 65 post-treatment, with an increasing visual trend indicating recontamination. This is the first report confirming a passthrough pseudoparasite in tenrecs from dubia roaches, and anthelmintic dosage research is warranted.

Supplemental Material for Influence of Group Size on Shelter Choice in Blaptica dubia Cockroaches

Supplemental Material for Influence of Group Size on Shelter Choice in Blaptica dubia Cockroaches

Comparing the aromatic profile of seven unheated edible insect species

Insects and insect-based products have gained increasing interest as human food because of their many technological, nutritional and environmental advantages, but they are still rejected by many Western consumers. Analytical knowledge of flavour compounds could contribute to enhancing product attractiveness to consumers. Therefore, the goal of this study was to examine the volatile compound profiles of 7 unheated insects: Zophobas morio (ZM), Tenebrio molitor (TM), Locusta migratoria (LM), Galleria mellonella (GM), Blaptica dubia (BD), Alphitobius diaperinus (ALD) and Acheta domesticus (ACD). A total of 67 compounds were identified. Carboxylic acids were predominant in ALD, BD, GM, TM and ZM, while ketones were the major family in ACD and linear hydrocarbons in LM. ZM contained the highest number of unpleasant odour compounds, including indole, also present in BD and GM, which is characterised by a low detection threshold.

Direct and indirect phenotypic effects on sociability indicate potential to evolve.

The decision to leave or join a group is important as group size influences many aspects of organisms' lives and their fitness. This tendency to socialise with others, sociability, should be influenced by genes carried by focal individuals (direct genetic effects) and by genes in partner individuals (indirect genetic effects), indicating the trait's evolution could be slower or faster than expected. However, estimating these genetic parameters is difficult. Here, in a laboratory population of the cockroach Blaptica dubia, I estimate phenotypic parameters for sociability: repeatability (R) and repeatable influence (RI), that indicate whether direct and indirect genetic effects respectively are likely. I also estimate the interaction coefficient (Ψ), which quantifies how strongly a partner's trait influences the phenotype of the focal individual and is key in models for the evolution of interacting phenotypes. Focal individuals were somewhat repeatable for sociability across a 3-week period (R= 0.080), and partners also had marginally consistent effects on focal sociability (RI= 0.053). The interaction coefficient was non-zero, although in opposite sign for the sexes; males preferred to associate with larger individuals (Ψmale = -0.129), while females preferred to associate with smaller individuals (Ψfemale = 0.071). Individual sociability was consistent between dyadic trials and in social networks of groups. These results provide phenotypic evidence that direct and indirect genetic effects have limited influence on sociability, with perhaps most evolutionary potential stemming from heritable effects of the body mass of partners. Sex-specific interaction coefficients may produce sexual conflict and the evolution of sexual dimorphism in social behaviour.

Selection and Validation of Potential Reference Genes for Quantitative Real-Time PCR Analysis in Blaptica Dubia (Serville, 1838) (Blattidae, Blaberidae)

Reverse transcription-quantitative polymerase chain reaction (RT-qPCR) is an effective, reproducible, and dependable method for evaluating and targeting expression of genes. It is very important to normalize according to stably expressed housekeeping genes in order to facilitating gene expression studies and to acquire exact and meaningful results. The purpose of this study was to identify and validate six housekeeping genes (GADPH, RPS18, α-TUB, EF1α, ArgK and ACTB) in adults of cockroach species Blaptica dubia employing five different algorithms (geNorm, Bestkeeper, Normfinder, ΔCt method and RefFinder) to assess putative housekeeping gene expression stability. Our study also showed that the geNorm, Normfinder ΔCt method and RefFinder algorithms identified GADPH as the most stable housekeeping gene in B. dubia adults. Additioanlly, RPS18 was suggested as the most stable gene by GeNorm and BestKeeeper. ACTB has been shown to be by far the least stable of all algorithms. In addition, since there are few validation studies for reference genes in cockroaches in the literature, it is considered that it would be beneficial to increase the number of studies related with RT-qPCR on the reference genes validation under biotic and abiotic conditions in cockroaches.

Dietary protein and sodium co‐limit cockroach growth and reproduction

Abstract Both dietary protein (N) and sodium (Na) are essential nutrients for invertebrate growth and reproduction. Field studies show that insects aggregate in areas with both high protein and sodium and their abundance is co‐limited by these two essential nutrients, but the mechanism behind this aggregation is not well known. We examined a possible mechanism that dietary protein and sodium co‐limit insect herbivore growth and reproduction. To test this mechanism, we conducted a feeding experiment examining the effect of these two nutrients by using artificial diets with two levels of protein and three levels of sodium on a generalist herbivorous cockroach Blaptica dubia. Elevated levels of dietary sodium interacted with low protein level to increase cockroach nymph relative growth rate during earlier instars. Female cockroaches always weighed more and had a higher relative growth rate than males regardless of dietary treatment. When compared between different dietary treatments, female cockroaches' relative growth rates were higher when fed with a high protein diet, while male cockroaches reached the final instar faster when fed with a high sodium diet. Cockroach reproduction was not affected by protein or sodium alone, but the combination of a high protein and high sodium diet resulted in the heaviest offspring. Our results suggest that both protein and sodium may be important for both the growth and reproduction of insect herbivores. The interaction of these two nutrients to improve cockroach growth and reproduction indicate a level of co‐limitation.

Essential oils loaded on polymeric nanoparticles: bioefficacy against economic and medical insect pests and risk evaluation on terrestrial and aquatic non-target organisms.

This paper introduces the lethal, sublethal, and ecotoxic effects of peppermint and palmarosa essential oils (EOs) and their polymeric nanoparticles (PNs). The physicochemical analyses indicated that peppermint PNs were polydisperse (PDI > 0.4) with sizes of 381nm and loading efficiency (LE) of 70.3%, whereas palmarosa PNs were monodisperse (PDI < 0.25) with sizes of 191nm and LE of 89.7%. EOs and their PNs were evaluated on the adults of rice weevil (Sitophilus oryzae L.) and cigarette beetle (Lasioderma serricorne F.) and the larvae of Culex pipiens pipiens Say. On S. oryzae and L. serricorne, PNs increased EOs' lethal activity, extended repellent effects for 84h, and also modified behavioral variables during 24h. Moreover, EOs and PNs generated toxic effects against C. pipiens pipiens. On the other hand, peppermint and palmarosa EOs and their PNs were not toxic to terrestrial non-target organisms, larvae of mealworm (Tenebrio molitor L.), and nymphs of orange-spotted cockroach (Blaptica dubia S.). In addition, PNs were slightly toxic to aquatic non-target organisms, such as brine shrimp (Artemia salina L.). Therefore, these results show that PNs are a novel and eco-friendly formulation to control insect pests.

Genome size evaluations in cockroaches: new entries.

In this paper, we report genome size (GS) values for nine cockroaches (order Blattodea, families Blattidae, Blaberidae and Ectobiidae, ex Blattelidae), three of which are original additions to the ten already present in the GS database: the death’s head roach (Blaberus craniifer), the Surinam cockroach (Pycnoscelus surinamensis) and the Madeira cockroach (Leucophaea maderae). Regarding the American cockroach (Periplaneta americana), the GS database contains two contrasting values (2.72 vs 3.41 pg); likely, the 2.72 pg value is the correct one as it is strikingly similar to our sperm DNA content evaluation (2.80 ± 0.11 pg). Also, we suggest halving the published GS of the Argentine cockroach Blaptica dubia and the spotted cockroach (the gray cockroach) Nauphoeta cinerea discussing i) the occurrence of a correlation between increasing 2n chromosome number and GS within the order Blattodea; and ii) the possible occurrence of a polyploidization phenomenon doubling a basic GS of 0.58 pg of some termite families (superfamily Blattoidea, epifamily Termitoidae).

Sex-Specific Effect of the Dietary Protein to Carbohydrate Ratio on Personality in the Dubia Cockroach.

Simple SummaryAnimal personality is modulated by genetic and environmental factors. To explore the modulatory effect of nutrition on personality, we investigated whether diets varying in their relative content of proteins and carbohydrates might modulate the behavior of the Dubia cockroach. Over a period of eight weeks, we fed adult cockroaches, both males and females, five different diets, and we measured diet consumption, survival, and personality traits by recording their exploratory and mobility behaviors. After eight weeks, females gained more body mass and had higher survival than males. We found that females preferred carbohydrate-rich diets and avoided ingesting too many proteins by consuming less food on high-protein diets. The diet had no effect on their personality. However, males showed a bolder personality when fed with high-protein diets while consuming the same amount of food, regardless of the protein content in the diet. These sex differences could be beneficial for the species in stressful nutritional environments, allowing males to discover new food resources while ovoviviparous females could spend more time protected in shelters.Animal personality, defined by behavioral variations among individuals consistent over contexts or time, is shaped by genetic and environmental factors. Among these factors, nutrition can play an important role. The Geometric Framework of Nutrition has promoted a better understanding of the role of the macronutrient proportion in animal development, survival, reproduction, and behavior, and can help to disentangle its modulatory effect on animal personality. In this study, we investigated the effects of protein to carbohydrate (P:C) ratio in the personality of the cockroach Blaptica dubia. Newly emerged adults were fed over a period of eight weeks on five different diets varying in their P:C ratio and their diet consumption, mass variation, survival, exploratory behavior, and mobility were assessed. We found that females, unlike males, were able to regulate their nutrient intake and preferred carbohydrate-rich diets. Females also gained more body mass and lived longer compared to males. In addition, their behavior and mobility were not affected by the diet. In males, however, high-protein diets induced a bolder personality. We suggest that the sex-specific effects observed on both survival and behavior are related to the nutrient intake regulation capacity and might improve the species’ fitness in adverse nutritional conditions.

Pinching or stinging? Comparing prey capture among scorpions with contrasting morphologies.

Background: Scorpions can use their pincers and/or stingers to subdue and immobilize their prey. A scorpion can thus choose between strategies involving force or venom, or both, depending on what is required to subdue its prey. Scorpions vary greatly in the size and strength of their pincers, and in the efficacy of their venom. Whether this variability is driven by their defensive or prey incapacitation functionis unknown. In this study, we test if scorpion species with different pincer morphologies and venom efficacies use these weapons differently during prey subjugation. To that end, we observed Opisthacanthus elatus and Chactas sp. with large pincers and Centruroides edwardsii and Tityus sp. with slender pincers.Methods: The scorpion pinch force was measured, and behavioral experiments were performed with hard and soft prey (Blaptica dubia and Acheta domesticus). Stinger use, sting frequency and immobilization time were measured.Results: We found that scorpions with large pincers such as O. elatus produce more force and use the stinger less, mostly subjugating prey by crushing them with the pincers. In C. edwardsii and Tityus sp. we found they use their slender and relatively weak pincers for holding the prey, but seem to predominantly use the stinger to subjugate them. On the other hand, Chactas sp. uses both strategies although it has a high pinch force. Conclusions: Our results show that scorpionspecies with massive pincers and high pinch force as O. elatus use the stinger less for prey subjugation than scorpionspecies with slenderpincers.