Action mode of fipronil and sulfluramid in baits on Acromyrmex crassispinus (Forel, 1909) (Hymenoptera: Formicidae) in laboratory conditions

The leaf-cutting ants (LCAs) of the genus Atta Fabricius, 1804 and Acromyrmex Mayr, 1865 (Hymenoptera: Formicidae) are major pests in forest plantations, agriculture and livestock. Toxic baits with the active ingredients fipronil and sulfluramid are the main method to manage these insects. The internal hygiene of the ant colony needs to be considered to carry out chemical control of LCA. The baits must act as a true ´Trojan horse´ deceiving the toxic action during the moment of transport. The objective was to evaluate fipronil and sulfluramid in toxic baits against Acromyrmex crassispinus (Forel, 1909) (Hymenoptera: Formicidae) in the laboratory. The action was observed in the first hours after application. The pick-up of the bait with fipronil was more heterogeneous and more random than that with the sulfluramid. Individuals of A. crassispinus stopped cutting leaves after four and seven days after application (DAA) of fipronil and sulfluramid baits, respectively. The foraging activity tended to zero over time with the sulfluramid bait, but a low carry of leaves was observed on the 11th DAA with the fipronil bait. The fipronil and sulfluramid baits, in laboratory conditions, were toxic and efficient to the ant A. crassispinus. The lethal action of fipronil was faster, an undesired aspect in the management of social insects. A control method that simulates the mythical ´Trojan horse´ on LCAs nests is desirable.Fil: Sabattini, Julian Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Entre Ríos. Facultad de Ciencias Agropecuarias; ArgentinaFil: Zanuncio, Jose C.. Universidade Federal de Viçosa; BrasilFil: Camargo, Roberto S.. Universidade Estadual Paulista Julio de Mesquita Filho; BrasilFil: Forti, Luiz C.. Universidade Estadual Paulista Julio de Mesquita Filho; Brasi

Post-embryonic Development of Intramandibular Glands in Pachycondyla verenae (Forel) (Hymenoptera: Formicidae) workers

The current knowledge of intramandibular glands in Hymenoptera is focused on occurrence and morphology in adult insects. This is the first report regarding the post-embryonic development of intramandibular glands in a “primitive” ant, Pachycondyla verenae. In this study, we analyzed mandibles of prepupae, white-eyed, pink-eyed and black-eyed pupae, pupa of pigmented body pupae, and adults. Adult workers of P. verenae have intramandibular glands with epidermal secretory cells of class I and isolated glands of class III, and both glands have onset differentiation in pink-eyed pupae. Some histological sections were submitted to histochemical test for total proteins and neutral polysaccharides. Histochemical tests showed occurrence of polysaccharides and proteins in epidermal secretory cells of class I from the white-eyed pupae, polysaccharides and proteins in pink-eyed pupae to black-eyed pupae in both glands classes I and III and presence of polysaccharides in adult ants also in both gland classes I and III. Intramandibular glands of classes I and III in P. verenae workers differentiate during pupation, with onset occurring in pink-eyed pupae, and completion occurring in black-eyed pupae

Fertility and life expectancy of a predatory stinkbug to sublethal doses of a pyrethroid

Podisus distinctus (Heteroptera: Pentatomidae) is an important predator used in biological control of eucalypt defoliating caterpillars, exposed the insecticides. Lower doses of permethrin not affect the values of generation time (T), time necessary to double the population in number of individuals (DT) and intrinsic rate of population increase (r m ). Moreover, females of P. distinctus derived from nymphs treated with lower doses of permethrin were more fertile, triggering the effect hormetic in net reproductive rates (Ro). Results showed that low permethrin doses can be used alongside the predatory stinkbug in Integrated Pest Management programs

Effect of the insect growth regulator diflubenzuron on the predator Podisus nigrispinus (Heteroptera: Pentatomidae)

Podisus nigrispinus (Dallas) (Heteroptera: Pentatomidae) is a common natural predator of defoliating caterpillars in agricultural and forest systems. Insecticides acting as growth regulators of insect pests can indirectly affect their predators through consumption of contaminated prey. We examined the reproductive performance of P. nigrispinus fed on caterpillars of Anticarsia gemmatalis Hubner (Lepidoptera: Noctuidae) reared on soybean leaves exposed to the chitin synthesis inhibitor, diflubenzuron. Caterpillars of A. gemmatalis were fed for 12 h with treated soybean leaves and offered to adults of the predator P. nigrispinus over five consecutive days. The fertility of P. nigrispinus was reduced when feeding on diflubenzuron treated caterpillars, especially at the beginning of the reproductive period, but recovered 3 weeks later. The effects of diflubenzuron ingestion on the life table parameters of P. nigrispinus included an increase in the period taken to double the population size, and reductions in the intrinsic rate of population increase, generation duration, and net reproductive rate. Diflubenzuron therefore had an indirect negative effect on the reproduction and the population dynamics of the non-target predator P. nigrispinus. Clearly, its use in integrated pest management requires further evaluation

Reproductive Tract Histology of Thaumastocoris peregrinus (Hemiptera: Thaumastocoridae)

The bronze bug Thaumastocoris peregrinus Carpintero & Dellape (Hemiptera: Thaumastocoridae) is a pest of Corymbia and Eucalyptus. Thus far, there are no effective control methods for this pest in commercial plantations. A study of the reproductive tract could provide basic strategies for controlling this insect. T. peregrinus females and males, of different ages, were obtained from mass rearing and analyzed using light microscopy. The male reproductive tract has a pair of testes with three globular follicles isolated by a peritoneal sheath, and two pairs of well-developed mesadenial tubular accessory glands. The female reproductive tract includes a pair of ovaries, each with two meroistic telotrophic ovarioles, opening into two long lateral oviducts, which joints in a short common oviduct. This common oviduct ends in a large and folded, thick-cuticle lined bursa copulatrix. Eggs with embryos in the stages of anatrepsis, catatrepsis, and post dorsal closure were found in the reproductive tract of females. The reproductive tract of T. peregrinus males and females are similar to those of other Thaumastocoridae, but differ in the number of ovarioles per ovary in its females.Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES

Hormetic responses of a stinkbug predator to sublethal doses of pyrethroid

Stressors can affect reproduction and longevity by impacting endocrine and immune systems but they may increase life span and stimulate reproduction. The effects of sublethal doses of permethrin topically applied on third instar nymphs of Podisus distinctus (Heteroptera: Pentatomidae) was evaluated. The weight of females survival of nymph and adults, number of eggs and nymphs/females of P. distinctus were higher when exposed to lower doses of permethrin. On the other hand, the exposition to the 0.131, 1.315 and 13.15 ppb showed positive effects on the oviposition periods, number of egg masses and longevity of P. distinctus females

First Record of a Native Heteropteran Preying on the Introduced Eucalyptus Pest, Thaumastocoris peregrinus (Hemiptera: Thaumastocoridae), in Brazil

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES

Prey digestion in the midgut of the predatory bug Podisus nigrispinus (Hemiptera: Pentatomidae)

Pre-oral digestion is described as the liquefaction of the solid tissues of the prey by secretions of the predator. It is uncertain if pre-oral digestion means pre-oral dispersion of food or true digestion in the sense of the stepwise bond breaking of food polymers to release monomers to be absorbed. Collagenase is the only salivary proteinase, which activity is significant (10%) in relation to Podisus nigrispinus midgut activities. This suggests that pre-oral digestion in P. nigrispinus consists in prey tissue dispersion. This was confirmed by the finding of prey muscles fibers inside P. nigrispinus midguts. Soluble midgut hydrolases from P. nigrispinus were partially purified by ion-exchange chromatography, followed by gel filtration. Two cathepsin L-like proteinases (CAL1 and CAL2) were isolated with the properties: CAL1 (14.7 kDa, pH optimum (pHo) 5.5, km with carbobenzoxy-Phe-Arg-methylcoumarin, Z-FR-MCA, 32 mu M); CAL2 (17 kDa, pHo 5.5, km 11 mu M Z-FR-MCA). Only a single molecular species was found for the other enzymes with the following properties are: amylase (43 kDa, pHo 5.5, km 0.1% starch), aminopeptidase (125 kDa, pHo 5.5, km 0.11 mM L-Leucine-p-nitroanilide), alpha-glucosidase (90 kDa, pHo 5.0, km 5 mM with p-nitrophenyl alpha-D-glucoside). CAL molecular masses are probably underestimated due to interaction with the column. Taking into account the distribution of hydrolases along P. nigrispinus midguts, carbohydrate digestion takes place mainly at the anterior midgut, whereas protein digestion occurs mostly in middle and posterior midgut, as previously described in seed- sucker and blood-feeder hemipterans. (C) 2012 Elsevier Ltd. All rights reserved.FAPESPFAPESPCNPqCNPqCAPESCAPESFAPEMIGFAPEMI

The biology and thermal requirements of the fennel aphid Hyadaphis foeniculi (Passerini) (Hemiptera: Aphididae)

The relationship between the insect development rate and temperature was established very early and represents an important ecological variable for modeling the population dynamics of insects. The accurate determination of thermal constant values and the lower and upper developmental thresholds of Hyadaphis foeniculi (Passerini) (Hemiptera: Aphididae) on fennel (Foeniculum vulgare Miller (Apiales: Apiaceae)) crops would obviously benefit the effective application of control measures. This paper is a study of the biology and thermal requirements of H. foeniculi. Winged insects were collected from fennel crops at the Embrapa Algodao in Campina Grande, Paraiba. Nymphs (age <= 24 h) produced by winged insects were subjected to constant temperatures of 15, 20, 25, 28, 30 or 33 degrees C, a photophase of 12 h and a relative humidity of 70 +/- 10%. The results of the study showed that at temperatures between 15 and 30 degrees C, H. foeniculi nymphs were able to develop normally. The four instars were found at all temperatures tested. However, temperatures of 3 and 33 degrees C were lethal to the nymphs. The nymph stage development time varied from 5 (30 degrees C) to 19 (15 degrees C) days. The influence of temperature on the development time is dependent on the instar. The base temperature (Tb) and the thermal constant (K) for the nymph stage were estimated at 11.2 degrees C and 107.5 degree-days, respectively. The shortest nymph development stage was observed at 30 degrees C, and the highest nymph viability (85.0%) was observed at 28 degrees C. This information can be used for developing phenological models based on the temperature and development rate relationships so that outbreaks of H. foeniculi in the fennel crop can be predicted, therefore improving the application of control programs targeting this fennel pest.Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq