Neotropical Entomology ISSN: 1519-566X journal homepage: www.scielo.br/ne

SCIENTIFIC NOTE Behavioral Evidence of an Ectoparasitic Interaction between Triatoma pseudomaculata Corrêa & Espínola (Heteroptera: Reduviidae) and Periplaneta americana (L.) (Blattodea: Blattidae) GB Pontes1, F Noireau2†*, MG Lorenzo1 1Centro de Pesquisas René Rachou, Fundação Oswaldo Cruz, Belo Horizonte, MG, Brasil 2Unité de Recherche 016, Institut de Recherche pour le Développement (IRD), Montpellier, France, *in memorian

Keywords Abstract Behavior, Chagas disease, cockroach, Triatomine The present work tested whether Triatoma pseudomaculata Corrêa & Espínola shows behavioral traits indicating that it is capable of Correspondence feeding on arthropods. We consistently observed nymphs extending Gina B Pontes, Centro de Pesquisas René their proboscis in the direction of cockroaches and attempting to bite. Rachou, Fiocruz, Av. Augusto de Lima 1715, Barro Preto, 30190-002, Belo Horizonte, MG, parts. Our results suggest that arthropod hemolymph represents Brasil; [email protected] Insectsan alternative presented source a preference of food forthat biting increases specific the cockroach survival bodyof T. Edited by Neusa Hamada – INPA pseudomaculata individuals undergoing long starvation.

Received 07 February 2011 and accepted 07 June 2011

Triatoma pseudomaculata Corrêa & Espínola is T. pseudomaculata were used a hematophagous insect capable of transmitting Trypanosoma cruzi, the etiological agent of Chagas instarsStarved of cockroach fifth instars were of fed ad libitum on rabbit food disease, to humans (Silveira & Vinhaes 1998). It is pelletsfor these and experiments presented 30-35as potential days after hosts. ecdysis. For each Different assay, frequently captured in human-associated ecotopes and three T. pseudomaculata nymphs were individually its distribution includes most of the semiarid northeast weighed, marked with paint and transferred to a Petri of Brazil. As for human environments, this species is dish (10 cm diameter) that was used as an experimental mostly found in peridomiciliary settings (Dias & Diotaiuti arena (15 replicates, 45 insects). A cockroach nymph (n 1998). = 15) was subsequently introduced in the arena and the Triatoma pseudomaculata has been found associated assay initiated. with cockroaches inside chicken-coops (Freitas et al the scotophase. An infrared sensitive CCD video camera of cockroach hemolymph in the intestinal contents of (HDL,The HM assays 30PB, were Brazil) conducted connected during to a time-lapse the first video- 6h of some2005), of andthe sampled precipitin insects. tests Our confirmed work tested the whether presence T. pseudomaculata presents behavioral traits indicative of behavior in the experimental arena. Triatomine nymphs arthropod feeding. We performed experiments in which wererecorder re-weighed (Samsung after SVR the 960NRT, assays to Korea) determine recorded whether bug nymphs of this species were confronted with those of they had ingested hemolymph. The following parameters Periplaneta americana (L.) and their behavior analyzed were analyzed: a) number of times that the rostrum of to characterize feeding interactions. nymphs contacted a cockroach, b) proportion of these

708 Neotrop Entomol 40(6): 708-710 © 2011 Sociedade Entomológica do Brasil Pontes et al Ectoparasitism of Periplaneta americana by Triatoma psedomaculata contacts on antennae, head, thorax, legs or abdomen of 30 P. americana * cockroach nymphs, i.e., alive or dead. Bugs from seven 25 out of 15 assays,, c) duration i.e., 21 bugs, of contacts were afterwards and d) final separated state of 20 in two groups: 1) insects that had increased their weight (7) and 2) insects that had not (14) and, their survival 15 rate was evaluated for two months. The duration of bites was analyzed sorting them in a total of eight 30s intervals 10 ranging from less than 30s (< 30s) to more than 210s (> 5 We observed nymphs extending their proboscides (mean ± s.e.) Number of bites 210s), e.g. 30-60s. 0 in the direction of cockroaches and carrying out biting Antenna Head Thorax Legs Abdomen Body structure assays (Fig 1). The minimum number of bites per assay attempts in 266 occasions distributed through all Fig 2 Distribution of bites (mean + s.e.) of Triatoma pseudomaculata a consequence, 29% of the insects (13/45) increased was six, while the maximum was 57 (33.2 ± 16.40). As body of cockroaches their weight after the experiment. Interestingly, fed bugs fifth instar nymphs on different parts of the presented an initial weight lower than those that did not (Kruskal-Wallis test, P = 0.006). feed (32/45, unpaired T test, t al 1999). Our data suggest that the pharmacological

-value = -3.68, df = 42 n be exclusively directed to facilitate vertebrate blood days= 45, allP = triatomines 0.0006), indicating in group that 1 (n low = 7) nutritional were still status alive. ingestion,effects of triatominebut also hemolymph salivary components intake through might thenot might have motivated them to bite arthropods. After 60 manipulation of arthropod motility. = Two out of 15 cockroaches died after the trials and Nevertheless,Triatomines only directed 29% of grouptheir 2bite (n =attempts 4/14) survived to all the number of triatomine bites was highest in both assays parts(difference of the cockroachbetween proportions body, but test,the choicesP 0.0069). were not (57 and 53). The death of P. americana nymphs may have et al frequently bitten body parts were the legs and head, random (Fig 2, Kruskal-Wallis, P = 0.035). The most beensaliva causedwas injected by specific into their effects hemolymph; on neurons the last(Dan being the number of bites on the legs and the thorax (Fig 2, the1999) least or probableby unspecific due totoxic the orfact proteolytic that most effectscockroaches when Dunn’sbut a significant post hoc differencemultiple comparison, was only observed P < 0.05). between The survived (13/15). Shortest and longest bite duration head, antennae and legs are structures that exhibit many sensory, integrative and motor components of the nervous system and concentrated 80% of the bites. durationintervals wereintervals the mostconcentrated frequent categoriesonly 104 of (< the 30 sbites. = 86 Additionally, it is known that triatomine saliva contains Thisbites, bimodal > 210 s =distribution 76 bites, respectively). was probably The due remaining to the fact six substances that affect nerve cell responses (Dan et that the bugs probed the body of the cockroach in short

insert their mouthparts and subsequently inject saliva. Hemolymphbursts (< 30 ingestions) in order would to find demand an adequate longer contactarea to periods and accordingly, the frequency of contacts longer than 210 seconds was also considerable. These long rostral contacts suggest that triatomines intended to feed on P. americana.

the Thestart proboscis of the feeding extension process reflex (Ferreira of triatomines et al 2007), is a whichbehavior was of observed extreme inimportance all the assays that carried frequently out. Thereflects fact that some of the nymphs increased weight after assays

This suggests that arthropod hemolymph represents an alternativeconfirms this source interpretation of food that of increasesprolonged the biting survival behavior. of T. pseudomaculata individuals undergoing long starvation. Therefore, triatomine bugs may have partially conserved Fig 1 Triatoma pseudomaculata their entomophagous habits during their evolution to the to feed on a cockroach, Periplaneta americana. haematophagous feeding specialization. fifth instar nymph attempting Neotrop Entomol 40(6): 708-710 © 2011 Sociedade Entomológica do Brasil 709 Ectoparasitism of Periplaneta americana by Triatoma psedomaculata Pontes et al

Acknowledgments Dias JCP, Diotaiuti L (1998) Vectores secundarios de la enfermedad de Chagas en el Brasil y perspectivas para su control, p.154-159. The authors thank ACL Lima for statistical advice, Dr. In Guhl F, Jaramillo CA, Control de tripanosomiasis americana Sharon Hill for her kind edition on the last version of y leishmaniosis: aspectos biológicos, genéticos y moleculares. the manuscript and the Institut de Recherche pour le Bogotá, Corcas Editores, 435p. Développement (IRD) and Fundação Oswaldo Cruz Ferreira RA, Lazzari CR, Lorenzo MG, Pereira MH (2007) Do haematophagous bugs assess skin surface temperature to detect

(FIOCRUZ) for financial support. This article is dedicated Freitasblood SPC, vessels? Lorosa PLoS ES, Rodrigues ONE 2: e-932. DCS, Freitas ALC, Gonçalves TCM diseasesto the memory that has of recently Dr. François passed Noireau, away. François a reference will forbe (2005) Fontes alimentares de Triatoma pseudomaculata no missedfield biologists by his colleagues, dedicated asto wellstudy as insect his great vectors contributions of human estado do Ceará, Brasil. Rev Saúde Pública 39: 27-32. Silveira AC, Vinhães M (1998) Doença de Chagas: aspectos epidemiológicos e de controle. Rev Soc Bras Med Trop 31: to our field. References 15-60. Dan A, Pereira MH, Pesquero JL, Diotaiuti L, Beirão PS (1999) Action of the saliva of Triatoma infestans (Heteroptera: Reduviidae) on

sodium channels. J Med Entomol 36: 875-879.

710 Neotrop Entomol 40(6): 708-710 © 2011 Sociedade Entomológica do Brasil