Grainy head signaling regulates epithelium development and ecdysis in Blattella germanica.

The transcription factor grainy head (Grh) functions in the protection of the epithelium against the external environment by generating strongly adhesive layers, and this function is conserved in vertebrates and invertebrates. In Drosophila, the top model for holometabolous insects, Grh is necessary during embryonic development, epidermal differentiation, central nervous system specification and epithelial repair. However, the function of this gene in hemimetabolous insect epithelia remains unknown. To examine the function of Grh signaling in regulating epithelium development in Hemimetabola, we focused on the Blattella germanica epidermal layer using a gene knockdown strategy. The spatiotemporal expression pattern of BgGrh was detected, and knockdown of BgGrh and BgCad96ca, which provide positive feedback to BgGrh, caused severe defects in new epithelium development and impeded the molting process required to discard the old integument. Knockdown of the expression of BgGrh and BgCad96ca caused increased expression of chitin synthase gene (BgCHS1) and chitinase gene (BgCht5), the upregulations of which should be mediated by the higher level of hormone receptor 3 (BgHr3) gene. In conclusion, epithelium development is regulated by Grh signaling, which might represent a potential target for the control of urban pest cockroaches.

The Persistence of Escherichia coli Infection in German Cockroaches (Blattodea: Blattellidae) Varies Between Host Developmental Stages and is Influenced by the Gut Microbiota.

The German cockroach, Blatella germanica (L.), is a suspected vector of several enteric bacterial pathogens, including Escherichia coli, among livestock and humans. However, little is known about the factors that influence bacterial transmission by cockroaches. Here, we orally infected B. germanica with various laboratory and field strains of E. coli and examined bacterial titers over time to shed new light on the factors that influence the dynamics of infection. Our results reveal that a laboratory strain of E. coli is largely cleared within 48 h while one field isolate can persist in a majority of cockroaches (80-100%) for longer than 3 d with minimal impact on cockroach longevity. We also find that the ability to clear some strains of E. coli is greater in cockroach nymphs than adults. Notably, no differential expression of the antimicrobial gene lysozyme was observed between nymphs and adults or in infected groups. However, clearance of E. coli was significantly reduced in gnotobiotic cockroaches that were reared in the absence of environmental bacteria, suggesting a protective role for the microbiota against exogenous bacterial pathogens. Together, these results demonstrate that the interactions between cockroaches and enteric bacterial pathogens are highly dynamic and influenced by a combination of microbial, host, and environmental parameters. Such factors may affect the disease transmission capacity of cockroaches in nature and should be further considered in both lab and field studies.

Instar Determination of Blattella asahinai (Blattodea: Ectobiidae) From Digital Measurements of the Pronotum Using Gaussian Mixture Modeling and the Number of Cercal Annuli.

The Asian cockroach, Blattella asahinai Mizukubo, has expanded its range throughout the southeastern United States since its introduction into Florida. Unlike its closest relative, the German cockroach, Blattella germanica (L.), B. asahinai lives outdoors and can fly. There is little information on the biology and development of B. asahinai, including the number of instars during nymphal development. To estimate the number of instars of B. asahinai, nymphs were photographed, sexed, and the lengths and widths of their pronota were measured digitally. The number of instars of B. asahinai was estimated using Gaussian mixture models with the pronotal data. The most probable model and its clusters were selected to assign individuals to an instar. Instars were also determined by counting the number of cercal annuli of nymphs. Both clustering and cercal annuli indicated that B. asahinai most frequently had six instars when reared at 30°C. Growth did not strictly follow the Brooks-Dyar Rule, because nymphs had different numbers of instars and different growth patterns. Although Gaussian mixture models are not efficient for field sampling experiments, digital measurements may provide a way to estimate instars with live specimens in development studies without handling the animals in a way that may alter growth.

Life history and functional capacity of the microbiome are altered in beta-cypermethrin-resistant cockroaches.

Cockroaches are widely perceived to evolve resistance to insecticides. Over-expression of a resistance-conferring gene can be costly and may require energy and resource reallocation for metabolic and developmental processes. To evaluate whether changes in the composition of gut microbiota in Blattella germanica affected its resistance evolution to beta-cypermethrin and to determine the role of gut microbiota in host growth and development, we studied the relationship between insecticide resistance and the diversity and genetic content of gut microbiota in cockroaches. Results suggest beta-cypermethrin-resistant cockroaches (R strain) exhibited a delayed development period and reduced adult longevity compared with susceptible cockroaches (S strain). Based on 16S rRNA gene sequencing and community metagenomics, we found that the relative abundance of Lactobacillus and Acetobacteraceae were significantly lower in the R strain compared with the S strain in the foregut and midgut of both strains. Functional annotation of Kyoto Encyclopedia of Genes and Genomes (KEGG) modules of midgut genes in the two strains revealed that 10.6% were involved in metabolism, while the relative abundance in the R strain was 7.4%. Unigenes were also translated into amino acid sequences and assigned to protein families based on hits to the Carbohydrate-Active enzymes (CAZy) database. This process identified the glycoside hydrolases, glycosyl transferases and carbohydrate-binding modules of the S strain as all being significantly higher in diversity than those in the R strain. Overall, we conclude that fitness-related costs increased in the resistant strain of cockroaches compared with the susceptible strain, and the variation in insect gut microbiota, especially those related to growth and development, was an important influencing factor.

Antibacterial/Antifungal Activity of Extracted Chitosan From American Cockroach (Dictyoptera: Blattidae) and German Cockroach (Blattodea: Blattellidae).

We investigated bactericidal and fungicidal properties of chitosan extracted from adults and nymphs from both German cockroach, Blattella germanica (Blattodea: Blattellidae) and American cockroach, Periplaneta americana (Dictyoptera: Blattidae). The cuticle of adults and nymphs extracted from both cockroaches were dried and ground. The powders were demineralized and deproteinized followed by deacetylation using NaOH. Finally, the chitosan yields were examined for antibacterial and antifungal activities. The degree of deacetylation (DD) was different between adults and nymph stages. The antimicrobial effect of American cockroach chitosan (ACC) and German cockroach chitosan (GCC) was tested against four bacteria and four fungi. The extracted chitosans from American cockroach, Periplaneta americana and German Cockroach, Blattella germanica suppressed the growth of Gram-negative/positive bacteria except Micrococcus luteus. The growth of Aspergillus flavus and Aspergillus niger were notability inhibited by the extracted chitosans. The antimicrobial effect of the chitosan depended on the cockroach species, with chitosan of the American cockroach showing more inhibitory effect. This difference may be due to differences in the structure of chitin between the two cockroach species.

TRANSMISSION OF PTERYGODERMATITES NYCTICEBI IN A COLONY OF GOELDI'S MONKEYS ( CALLIMICO GOELDII) AND EVALUATION OF TREATMENT AND CONTROL.

Over a 2-yr period, four Goeldi's monkeys ( Callimico goeldii) died in a private zoo due to infections with the spirurid nematode Pterygodermatites nycticebi. Therapeutic measures with different anthelmintics were not successful. Due to the severe consequences caused by these infections, different actions were initiated, including sanitation measures and controlling of potential intermediate hosts (coprophagous arthropods). To identify possible intermediate hosts, arthropod species detected in the enclosure-parasite-free German cockroaches ( Blattella germanica), European earwigs ( Forficula auricularia), and rough woodlice ( Porcellio scaber)-were experimentally fed with feces of monkeys with patent P. nycticebi infections, resulting in established infections with third-stage larvae (L3) in roaches and earwigs. Furthermore, spiruroid L3 were detectable in 43% of the roaches and 30% of earwigs caught at the zoo. Polymerase chain reaction and sequence analysis of eggs, larval, and adult stages resulted in identical results, confirming the establishment of the parasite's life cycle in the zoo. This is the first documentation of the vector capacity of the European earwigs for P. nycticebi. As a measure of sanitation, a large part of the enclosure was emptied and cleaned. The Goeldi's monkeys were quarantined and treated with levamisole (7.5 mg/kg sc twice in intervals of 2 wk). Repeated coprologic examinations by zinc chloride flotation were undertaken. After the levamisole therapy, eggs were not found in the feces for 3 mo. However, shortly after resettling the monkeys into the sanitized enclosure, reshedding of small amounts of spirurid eggs was observed, whereupon deworming with levamisole was prescribed several times per year. The sanitation measures and the elimination of the intermediate hosts in a natural enclosure are presented as an example of the long-term controlling of the parasites.

Diversity of piRNA expression patterns during the ontogeny of the German cockroach.

The Piwi-interacting RNA (piRNA) system is an evolutionarily conserved mechanism involved in the control of transposable elements and maintenance of genomic stability, especially in germ line cells and in early embryo stages. However, relevant particularities, both in mechanism and function, exist across species among metazoans and even within the insect class. As a member of the scarcely studied hemimetabolan group, Blattella germanica can be a suitable reference model to study insect evolution. We present the results of a stringent process of identification and study of expressed piRNAs for B. germanica across 11 developmental stages, ranging from unfertilized egg to nymphs and adult female. Our results confirm the dual origin of piRNA in this species, with a majority of them being generated from the primary pathway, and a smaller but highly expressed set of sequences participating in the secondary ("ping-pong") reamplification pathway. An intriguing partial complementarity in expression is observed between the piRNA of the two biogenesis pathways, with those generated in the secondary pathway being quite restricted to early embryo stages. In addition, many piRNAs are exclusively expressed in late embryo and nymphal stages. These observations point at piRNA functions beyond the role of transposon control in early embryogenesis. Our work supports the view of a more complex scenario, with different sets of piRNAs acting in different times and having a range of functions wider than previously thought.

Remodeling of the juvenile hormone pathway through caste-biased gene expression and positive selection along a gradient of termite eusociality.

The evolution of division of labor between sterile and fertile individuals represents one of the major transitions in biological complexity. A fascinating gradient in eusociality evolved among the ancient hemimetabolous insects, ranging from noneusocial cockroaches through the primitively social lower termites-where workers retain the ability to reproduce-to the higher termites, characterized by lifetime commitment to worker sterility. Juvenile hormone (JH) is a prime candidate for the regulation of reproductive division of labor in termites, as it plays a key role in insect postembryonic development and reproduction. We compared the expression of JH pathway genes between workers and queens in two lower termites (Zootermopsis nevadensis and Cryptotermes secundus) and a higher termite (Macrotermes natalensis) to that of analogous nymphs and adult females of the noneusocial cockroach Blattella germanica. JH biosynthesis and metabolism genes ranged from reproductive female-biased expression in the cockroach to predominantly worker-biased expression in the lower termites. Remarkably, the expression profile of JH pathway genes sets the higher termite apart from the two lower termites, as well as the cockroach, indicating that JH signaling has undergone major changes in this eusocial termite. These changes go beyond mere shifts in gene expression between the different castes, as we find evidence for positive selection in several termite JH pathway genes. Thus, remodeling of the JH pathway may have played a major role in termite social evolution, representing a striking case of convergent molecular evolution between the termites and the distantly related social hymenoptera.

Deltamethrin-resistant German Cockroaches Are Less Sensitive to the Insect Repellents DEET and IR3535 than Non-resistant Individuals.

The German cockroach, Blattella germanica (L.) (Blattodea: Blattellidae), is a serious worldwide pest with a considerable economical and sanitary impact. It is mainly controlled by the application of synthetic insecticides, but repeated use of these substances has promoted the appearance of resistance in cockroach populations throughout the world. The aim of this study was to compare the behavior of deltamethrin-susceptible (CIPEIN colony) and deltamethrin-resistant (JUBA and VGBA colonies) first instar nymphs exposed to the repellents N,N-diethyl-3-methylbenzamide (DEET) and ethyl 3-[acetyl(butyl)amino]propanoate (IR3535). Firstly, the behavior of the nymphs was assessed in an experimental arena in the absence of repellents. The parameters Distance Traveled, Velocity, Mobility Time, and Time Spent (in each half of the arena) were quantified using an image analyser, and showed that the behavior elicited by the three colonies was similar. After this, the behavior of the nymphs was quantified in an arena, half of which had been treated with repellent. The repellency of DEET increased as a linear function of log concentration for the three colonies. DEET elicited repellency as from a concentration of 97.49 µg/cm2 for the CIPEIN and JUBA colonies and 194.98 µg/cm2 for the VGBA colony. The repellency of IR3535 was weaker and started at a concentration of 389.96 µg/cm2 for the CIPEIN colony, 779.92 µg/cm2 for JUBA, and 1559.84 µg/cm2 for VGBA . Finally, nymphs were exposed to 3:1, 1:1, and 1:3 DEET:IR3535 mixtures, and a synergistic effect was observed only in the CIPEIN colony.

Expression of juvenile hormone acid O-methyltransferase and juvenile hormone synthesis in Blattella germanica.

Juvenile hormone (JH), a sesquiterpenoid synthetized by the insect corpora allata (CA), plays critical roles in metamorphosis and reproduction. Penultimate or last step of JH synthesis is catalyzed by juvenile hormone acid O-methyltransferase (JHAMT). Here we report the cloning and expression analysis of the JHAMT orthologue in the cockroach, Blattella germanica (L.) (BgJHAMT). BgJHAMT is mainly expressed in CA, with only expression traces in ovary. Three different isoforms, differing in the 3'-UTR sequence, were identified. Isoform A shows between 35 and 65 times higher expression than B and C in CA from penultimate nymphal instar and adult females. RNAi-triggered knock down of BgJHAMT produces a dramatic reduction of JH synthesis, concomitant with a decrease of fat body vitellogenin expression and basal follicle length. BgJHAMT mRNA levels in CA of females along the gonadotrophic cycle parallel, with a slight advancement, JH synthesis profile. BgJHAMT mRNA levels were reduced in starved females and in females in which we reduced nutritional signaling by knocking down insulin receptor and target of rapamycin (TOR). Results show that conditions that modify JH synthesis in adult B. germanica females show parallel changes of BgJHAMT mRNA levels and that the JH-specific branch of the JH synthesis pathway is regulated in the same way as the mevalonate branch. Furthermore, we demonstrate that nutrition and its signaling through the insulin receptor and TOR pathways are essential for activating BgJHAMT expression, which suggests that this enzyme can be a checkpoint for the regulation of JH production in relation to nutritional status.

New Food Baits for Trapping German Cockroaches, Blattella germanica (L.) (Dictyoptera: Blattellidae).

German cockroaches (GCRs), Blattella germanica (L.) (Dictyoptera: Blattellidae), are attracted to those beer semiochemicals (e.g., ethanol) that formerly living and active yeasts have produced or otherwise formed in the brewing process. We predicted that an earlier step in the production of beer, where yeasts actively metabolize the sugar in malted barley powder (dry malt extract [DME]), is very attractive to GCRs. In laboratory experiments, a 3-component composition (3CC) comprising DME, water, and Brewer's yeast strongly attracted GCR nymphs, females, and males. Both Brewers' yeast and 'spoilage organisms' in the DME or water seem to add to the attractiveness of the 3CC, but there is no additive or synergistic effect between them. The 3CC becomes optimally attractive to GCRs after 12 h of fermentation and stays that attractive for at least 120 h. In field trapping experiments, the 3CC and-unexpectedly-also the DME each proved as effective for attracting and capturing GCRs as a commercial cockroach bait (Combat Roach Gel). Future studies will investigate lethal biocontrol agents that can be added to the 3CC, or the DME, and will explore the efficacy of such lethal baits for GCR control.

Comparative analysis of miRNA expression during the development of insects of different metamorphosis modes and germ-band types.

BACKGROUND: Do miRNAs contribute to specify the germ-band type and the body structure in the insect embryo? Our goal was to address that issue by studying the changes in miRNA expression along the ontogeny of the German cockroach Blattella germanica, which is a short germ-band and hemimetabolan species. RESULTS: We sequenced small RNA libraries representing 11 developmental stages of B. germanica ontogeny (with especial emphasis on embryogenesis) and the changes in miRNA expression were examined. Data were compared with equivalent data for two long germ-band holometabolan species Drosophila melanogaster and Drosophila virilis, and the short germ-band holometabolan species Tribolium castaneum. The identification of B. germanica embryo small RNA sequences unveiled miRNAs not detected in previous studies, such as those of the MIR-309 family and 54 novel miRNAs. Four main waves of miRNA expression were recognized (with most miRNA changes occurring during the embryonic stages): the first from day 0 to day 1 of embryogenesis, the second during mid-embryogenesis (days 0-6), the third (with an acute expression peak) on day 2 of embryonic development, and the fourth during post-embryonic development. The second wave defined the boundaries of maternal-to-zygotic transition, with maternal mRNAs being cleared, presumably by Mir-309 and associated scavenger miRNAs. CONCLUSION: miRNAs follow well-defined patterns of expression over hemimetabolan ontogeny, patterns that are more diverse during embryonic development than during the nymphal stages. The results suggest that miRNAs play important roles in the developmental transitions between the embryonic stages of development (starting with maternal loading), during which they might influence the germ-band type and metamorphosis mode.

Persistence of a sugar-rejecting cockroach genotype under various dietary regimes.

Glucose-aversion is a heritable trait that evolved in a number of German cockroach (Blattella germanica L.) populations in response to strong selection with glucose-containing insecticide baits. However, in the absence of glucose-containing bait, glucose-averse (GA) cockroaches have lower performance than wild-type (WT) cockroaches in several fitness-determining traits. We allocated 48 caged populations initiated with homozygous GA and WT adults to four dietary treatments consisting of either pure rodent chow, rodent chow mixed to yield a content of either 20% glucose or 20% fructose, or a treatment consisting of choice between the 20% glucose- and the 20% fructose-containing food. After 6 months we found significantly higher frequency of WT individuals in populations restricted to the 20% glucose food, and after 12 months all dietary treatments contained significantly more WT individuals than expected. In accompanying experiments, we found lower survival and longer development time of GA nymphs restricted to glucose-containing food. We furthermore found evidence for assortative mating of females with males from their own genotype, with significant differences within WT cockroaches. Our study shows experimental evidence that within heterogeneous populations, WT German cockroaches will over time prevail in abundance over GA individuals, even when glucose is not a dietary component.

Juvenile hormone biosynthesis in adult Blattella germanica requires nuclear receptors Seven-up and FTZ-F1.

In insects, the transition from juvenile development to the adult stage is controlled by juvenile hormone (JH) synthesized from the corpora allata (CA) glands. Whereas a JH-free period during the last juvenile instar triggers metamorphosis and the end of the growth period, the reappearance of this hormone after the imaginal molt marks the onset of reproductive adulthood. Despite the importance of such transition, the regulatory mechanism that controls it remains mostly unknown. Here, using the hemimetabolous insect Blattella germanica, we show that nuclear hormone receptors Seven-up-B (BgSvp-B) and Fushi tarazu-factor 1 (BgFTZ-F1) have essential roles in the tissue- and stage-specific activation of adult CA JH-biosynthetic activity. Both factors are highly expressed in adult CA cells. Moreover, RNAi-knockdown of either BgSvp-B or BgFTZ-F1 results in adult animals with a complete block in two critical JH-dependent reproductive processes, vitellogenesis and oogenesis. We show that this reproductive blockage is the result of a dramatic impairment of JH biosynthesis, due to the CA-specific reduction in the expression of two key JH biosynthetic enzymes, 3-hydroxy-3-methylglutaryl coenzyme A synthase-1 (BgHMG-S1) and HMG-reductase (BgHMG-R). Our findings provide insights into the regulatory mechanisms underlying the specific changes in the CA gland necessary for the proper transition to adulthood.

Effects of foraging distance on macronutrient balancing and performance in the German cockroach Blattella germanica.

The German cockroach (Blattella germanica) is an excellent model omnivore for studying the effect of foraging effort on nutrient balancing behavior and physiology, and its consequences for performance. We investigated the effect of foraging distance on individual German cockroaches by providing two foods differing in protein-to-carbohydrate ratio at opposite ends of long containers or adjacent to each other in short containers. Each food was nutritionally imbalanced, but the two foods were nutritionally complementary, allowing optimal foraging by selective feeding from both foods. We measured nutrient-specific consumption in fifth instar nymphs and newly eclosed females foraging at the two distances, hypothesizing that individuals foraging over longer distance would select more carbohydrate-biased diets to compensate for the energetic cost of locomotion. We then determined dry mass growth and lipid accumulation in the nymphs as well as mass gain and the length of basal oocytes in the adult females as an estimate of sexual maturation. Nymphs foraging over longer distance accumulated less lipid relative to total dry mass growth, but contrary to our predictions, their protein intake was higher and they accumulated more structural mass. In concordance, adult females foraging over longer distance gained more body mass and matured their oocytes faster. Our results show a positive effect of foraging distance on fitness-related parameters at two life stages, in both cases involving increased consumption of specific nutrients corresponding to requirements at the respective life stage.

An annotated checklist and key to the Bulgarian cockroaches (Dictyoptera: Blattodea).

An annotated checklist of the Bulgarian species of cockroaches is prepared based on a full published scientific record and own unpublished data. According to the current state of knowledge the Bulgarian cockroach fauna includes 17 species and subspecies. One synonymization is established-Phyllodromica marginata erythronota Br. v. W., syn. n. = Ph. marginata. Two species (Capraiellus tamaninii and Supella longipalpa) are recorded for the first time for this country and other three (Ectobius punctatissimus, Phyllodromica subaptera and Phyllodromica pallida) are eliminated from the list of the Bulgarian fauna. The list is complemented with maps and full locality data and a dichotomic identification key for the studied taxa is presented.

A taxonomic report on the cockroach genus Haplosymploce Hanitsch from China including one new species (Blattodea: Ectobiidae: Blattellinae).

The cockroach genus Haplosymploce Hanitsch is recorded from China for the first time with two species: H. andamanica (Princis, 1951) from Yunnan which was originally recorded from Andaman, and H. aurantiaca sp. n. from Hainan, a phototactic species remarkable by the orangish yellow cerci, it is very likely to be a wood-feeding species and thus, along with the genus, stands out among Ectobiidae (=Blattellidae). Male of both and female of H. aurantiaca sp. n. are described, illustrated and photographed; the female genitalia of the new species show a high degree of asymmetry. Photos of H. aurantiaca sp. n. in the wild are provided, as well as a key to the males of 8 out of 11 known species worldwide.

Contribution to the knowledge of Lanta Hebard, 1921, with remarks on some male genital characters (Blattaria, Ectobiidae).

The genus Lanta Hebard 1921 includes three species found in the Neotropical region. Two species are known from Argentina, L. peniculiger (province of Santa Fe), and L. scotia (provinces of Córdoba and Santiago del Estero) (see Crespo et al. 2010), and one from Brazil, L. borgesae, (Araras, São Paulo) (Rocha e Silva & Vasconcellos, 1984). All species have been described on the basis of male external characters, such as wing veins, leg spines, hypandrium, shape and position of the styli, in addition to coloration and size. Except for a partial representation of the male genitalia of L. borgesae (Rocha e Silva & Vasconcellos 1984), this structure went untreated in morphological and phylogenetic investigations of the Blattaria (Snodgrass 1937; McKittrick 1964; Grandcolas 1996; Klass 1997; Roth 2003;). Females remain unknown.

Diet quality affects bait performance in German cockroaches (Dictyoptera: Blattellidae).

BACKGROUND: Bait formulations are widely used to control German cockroach (Blattella germanica) populations. To perform optimally, these formulations must compete favorably with non-toxic alternative foods present within the insect's habitat. We hypothesized that the nutritional history of cockroaches and their acceptance or avoidance of glucose would affect their food preference and thus bait efficacy. To test this hypothesis, we conducted a controlled laboratory experiment, first providing glucose-accepting and glucose-averse cockroaches nutritionally defined diets and then offering them identical diets containing the insecticide hydramethylnon as a bait proxy to evaluate the effect of diets of differing macronutrient composition on bait performance. RESULTS: The interaction between diet composition and bait composition affected the survival of adult males as well as first-instar nymphs exposed to excretions produced by these males. Survival analyses indicated different responses of glucose-averse and glucose-accepting insects, but generally any combination of diet and bait that resulted in high diet intake and low bait intake reduced secondary kill. CONCLUSIONS: This study represents a comprehensive examination of the effect of alternative foods on bait efficacy. We suggest that disparities between the nutritional quality of baits and the foods that are naturally available could profoundly impact the management of German cockroach infestations. © 2016 Society of Chemical Industry.

Gold-nanoparticles ingestion disrupts reproduction and development in the German cockroach.

The present work shows the effects of gold nanoparticles (AuNPs) orally administered on reproduction and development of the insect Blattella germanica. Newly emerged females were provided with food containing AuNPs (87.44µg/g) of a size between 15 and 30nm (mean 21.8nm), and were allowed to mate with males. Food ingestion, mortality, reproductive parameters (time to ootheca formation and eclosion, ootheca viability and fertility) as well as postembryonic developmental parameters of the first ootheca (nymphal survival and life span) were recorded throughout the experiment. Gold from AuNPs was accumulated by adults of B. germanica with a bioaccumulation factor of 0.1. Ingestion of AuNPs did not disturb the time for ootheca formation nor ootheca eclosion. However, ootheca viability was decreased almost by 25% in AuNPs treated females in comparison to controls. At the same time the number of hatched nymphs was decreased by 32.8% (p<0.001) in AuNP group respect to control one. The postembryonic developmental parameters were also affected by AuNPs treatment, with a 35.8% of decrease (p<0.01) in number of nymphs that moulted to second and third instars and a reduction of their life span. Ingestion of AuNPs causes sublethal effects in B. germanica that compromises life-traits involved in population dynamics. B. germanica is proposed as a model species in nanotoxicological studies for urban environments.