Duration Of Pupal Stages Research Articles

Laboratory Evaluation of a Biorational Insecticide, Kinoprene, against Culex pipiens Larvae: Effects on Growth and Development

ABSTRACT Aims: In the present study, the objective was to estimate the toxicity of an insect growthregulator with juvenile hormone-like activity, kinoprene, on Culex pipiens, the mostabundant and investigated mosquito species. Effects of this compound on growth anddevelopment were also evaluated.Methodology: A commercial formulation (Enstar 65% EC) was tested at differentconcentrations ranging between 162.5 and 650µg/L on newly molted fourth-instar larvaethat were exposed for 24 h under standard laboratory conditions according to WorldHealth Organization recommendations.Results: Kinoprene exhibited insecticidal activity by direct action on the treated fourth-instar larvae but also by differed action on the other following stages of development.Mortality occurred after earlier inhibition of their development or by their inability tocomplete their ecdysis. The LC 50 values were 1287.4µg/L for the direct action on fourthinstar larvae, and 246.8µg/L for the differed action until adult emergence. Moreover, thecompound disturbed growth and development since several morphological types and anincrease in the duration of larval and pupal stages were recorded. In a second series ofexperiments, the effects of kinoprene were examined on morphometric measurements ofOriginal Research Article

Prospecting of popcorn hybrids for resistance to fall armyworm.

The fall armyworm, Spodoptera frugiperda, is the pest that causes the greatest economic losses for both common corn and popcorn crops, and the use of resistant plant genotypes is an important tool for integrated pest management. The goal of the present study was to evaluate the damage caused by S. frugiperda on single-cross popcorn hybrids under field conditions with natural infestation as well as to study the effect of 11 popcorn hybrids on the S. frugiperda life cycle under laboratory conditions. A completely randomized block design with 4 replicates was used for the field experiment, and a completely randomized design with 10 replicates was used for the laboratory experiment. In the field experiment, the damage caused by fall armyworm, grain yield, and popping expansion were quantified, and a diallel analysis was performed to select the best hybrids. For the laboratory experiment, caterpillars were obtained from laboratory cultures kept on an artificial diet and were fed with leaves from the 11 hybrids. Hybrids P7.0 x P9.4, P7.1 x P9.6, P7.2.0 x P9.3, P7.4.0 x P9.1 and P7.4.1 x P9.4 exhibited negative specific combining ability for injury by fall armyworm and positive specific combining ability for yield and popping expansion. In the laboratory experiment, the hybrids influenced the mean larval stage duration, mean larval mass, final larval mass, pupal stage duration, mean pupal mass, and adult longevity.

Effects of the antibiotics Gentamicin on the postembryonic development of Chrysomya putoria (Diptera: Calliphoridae).

We evaluate the effects the antibiotic Gentamicin on the development of Chrysomya putoria (Wiedemann, 1818). Third-generation, first-instar larvae were reared in a climatic chamber on 60 g of homogenate + agar 65% and were treated with three concentrations of Gentamicin: 4.44 mg/ml, 13.33 mg/ml, and 66.66 mg/ml. The control consisted of distilled water. The relationships between mean body mass of mature larvae (measured after diet abandonment, in batches of five individuals), duration of larval and pupal stages, and overall duration of development were analyzed. The actual sex ratio was compared against the expected using the chi square. None of the parameters measured differed significantly among the four treatments, with one exception: when Gentamicin concentration was 13.33 mg/ml, larval viability differed significantly from the control. All larvae from all treatments were considered normal. We conclude that the antibiotic did not significantly alter the development of C. putoria (Wiedemann) (Diptera: Calliphoridae).

Effects of temperature on the development and population growth of the melon thrips, Thrips palmi, on eggplant, Solanum melongena.

The effects of temperature on the melon thrips, Thrips palmi Karny (Thysanoptera: Thripidae), preimaginal development, survival, fecundity, longevity of females and males, and population growth were investigated at 16, 19, 22, 25, 28, and 31° C, 70–80% RH, and a photoperiod of 12:12 L:D. The results indicated that the duration of egg, larval, and pupal stages was significantly influenced by increased temperature. The egg-to-adult developmental period of T. palmi declined from 35.7 to 9.6 days as the temperature increased from 16 to 31° C. The developmental threshold temperature estimated for egg-to-adult was 11.25° C, with a thermal constant of 196.1 degreedays. The developmental threshold temperature was 13.91, 11.82, 9.36, and 10.45° C for adult preoviposition period, total preoviposition period, female longevity, and male longevity, respectively. The thermal constants for completing the adult preoviposition period, total preoviposition period, female longevity, and male longevity were 29.3, 227.3, 454.6, and 344.8 degreedays, respectively. Female longevity was found to be shortest at 31° C (18.7 days) and longest at 16° C (56.7 days), and male longevity was shortest at 31° C (15.5 days) and longest at 16° C (50.7 days). Fecundity was highest at 25° C (64.2 eggs/female) and lowest at 16° C (23.4 eggs/female). The population trend index of T. palmi was highest at 25° C (31.3) and lowest at 16° C (7.6). The optimal developmental temperature for T. palmi in eggplant, Solanum melongena L. (Solanales: Solanaceae), was determined to be 25° C.

Immature Stages and Life Cycle of the Wasp Moth,Cosmosoma auge(Lepidoptera: Erebidae: Arctiinae) under Laboratory Conditions

Cosmosoma auge(Linnaeus 1767) (Lepidoptera: Erebidae) is a Neotropical arctiid moth common in Cuban mountainous areas; however, its life cycle remains unknown. In this work,C. augelife cycle is described for the first time; also, immature stages are described using a Cuban population. Larvae were obtained from gravid wild females caught in Viñales National Park and were fed with fresh leaves of its host plant, the climbing hempweedMikania micranthaKunth (Asterales: Asteraceae), which is a new host plant record. Eggs are hemispherical and hatching occurred five days after laying. Larval period had six instars and lasted between 20 and 22 days. First and last larval stages are easily distinguishable from others. First stage has body covered by chalazae and last stage has body covered by verrucae as other stages but has a tuft on each side of A1 and A7. Eggs and larvae features agree with Arctiinae pattern. Pupal stage lasted eight days, and, in general, females emerge before males as a result of pupal stage duration differences between sexes.

Effect of Various Kinds of Dietary Proteins In Semi – Artificial Diets on the Mulberry Silkworm Bombyx mori L.

Larvae of Bombyx mori were reared on various kinds of dietary protein (soybean, mushroom and mixture of them) using semi-artificial diet. Larvae fed on semi-artificial diet containing soybean all over the 5 th instar larvae gave the highest records on the larval duration, weights of larvae, silk gland, pupa, cocoon and cocoon shell, as well as number of deposited eggs. The same diet gave the lowest mortality percentages. The lower weights were calculated from larvae fed on mushroom diet. Insignificant differences were recorded on the pupal stage duration. Same trend of results were indicated for the larvae fed on the same materials till the 5 th day of the last instars then fed on natural diet.

Biology and life table of Dirphia araucariae (Lepidoptera: Saturniidae): A herbivore of potentially high impact on Araucaria angustifolia

The life-history and biology of Dirphia araucariae Jones, 1908, including its life fertility table, are here described. Moths were reared in the laboratory under controlled conditions on their host plant, Araucaria angustifolia (Bertoloni) O. Kuntze - Araucariaceae. We describe several life-history traits of the species, namely: developmental period, survival rate, growth rate, fertility, fecundity, sex ratio, cephalic capsule width, and pupal weight. Mean duration of life stages were: egg = 26.78 days; larva = 61.78 days; prepupa = 6.85 days; pupa = 62.46 days; adult = 8.37 days. We found statistically significant differences between sexes for adult, larval and pupal stage duration; larval stage was longer in females while pupal stage was longer in males. The survival rate of each life stage was: egg = 96.18%; larva = 95.38%; prepupa = 83.87%; pupa = 100%. The larvae developed through six instars and the mean growth rate was 1.418. The width of male and female cephalic capsules were different in last three instars, even though the total mean width between sexes was not different. Pupal mean weight ranged from 2.40 g to 4.79 g, with females being heavier than males. Fertility ranged from 66.78% to 100%, and the total fecundity was 358.45 eggs/female, including both laid eggs and eggs held in the abdomen. The sex ratio was 0.50 ± 0.05. The estimated biotic potential was 48731.08 specimens/female/year. We found the following values for the fertility life table: (Ro) = 117.21 females; (T) = 162.75 days; (r m) = 0.21; (l) = 1.23. Considering the biological parameters evaluated in this study, we conclude that D. araucariae is not able to cause primary damage in A. angustifolia forests, although further studies are needed to understand the reasons for occasional population outbreaks.

Fitness cost of resistance to Bacillus thuringiensis in velvetbean caterpillar Anticarsia gemmatalis Hübner (Lepidoptera, Noctuidae)

Selection pressure to obtain resistant genotypes can result in fitness cost. In this study, we report the effects of the selection pressure of a commercial formulation of Bacillus thuringiensis on biological aspects of a Dipel-resistant strain of velvetbean caterpillar, Anticarsia gemmatalis Hübner. Comparisons of Dipel-resistant and susceptible individuals revealed significant differences in pupal weight and larval development time. Both strains (Dipel-resistant and susceptible) were susceptible to Cry1Ac toxin expressed in foliar cotton tissues. Resistant and susceptible strains showed low survival rates of 22.5% and 51.2%, respectively, when fed with Greene diet containing Bt-cotton. Larvae bioassayed after three laboratory generations presented lower survival and less instar numbers than individuals maintained in the laboratory for more than 144 generations. Pupal weight was 9.4% lower and larval development time was 1.9 days longer in the resistant population than in the susceptible strain. Other parameters, such as duration of pupal stage, adult longevity, number of eggs per female, oviposition period, and egg fertility, remained unaffected.

Biological and behavioral parameters of the parasitoid Cotesia flavipes (Hymenoptera: Braconidae) are altered by the pathogen Nosema sp. (Microsporidia: Nosematidae)

A major issue for mass rearing of insects concerns sanitary conditions and disease. Microsporidian infection (Nosema sp.) in laboratory colonies of Diatraea saccharalis (Fabr.) (Lepidoptera: Crambidae), used in producing the parasitoid, Cotesia flavipes Cameron (Hymenoptera: Braconidae), is representative of the problems faced by growers and industry. Although C. flavipes has been produced for several years in Brazil for biological control of D. saccharalis, we have only recently observed that the parasitoid becomes infected when developing inside hosts infected with Nosema sp. We assessed the effects of Nosema sp. on C. flavipes, including the ability to locate and select hosts, and evaluated pathogen transmission. Third instar larvae of D. saccharalis were inoculated with Nosema sp. spores at different concentrations and were parasitized when larvae reached fifth instar. Heavily infected D. saccharalis larvae did not support parasitism. Parasitoids that developed in infected D. saccharalis larvae exhibited increased duration of larval and pupal stages, decreased adult longevity and number of offspring, and reduced tibia size compared to parasitoids developing in uninfected D. saccharalis larvae. Infection by Nosema sp. reduced the ability of the C. flavipes parasitoid to distinguish between volatiles released by the sugarcane infested by healthy larvae and pure air. Uninfected parasitoids preferred plants infested with uninfected hosts. But infected C. flavipes did not differentiate between uninfected hosts and those infected with Nosema sp. The pathogen is transmitted from host to parasitoids and parasitoids to hosts. Pathogenic effects of the microsporidium in C. flavipes are sufficiently severe to justify disease management efforts, particularly considering the importance of C. flavipes as a biological control agent in sugarcane.

Sublethal effects of methoxyfenozide on reproduction of the Mediterranean flour moth, Ephestia Kuehniella Zeller

Methoxyfenozide is a lepidopteran-specific insecticide belonging to a new class of insect growth regulator, the non-steroidal ecdysteroid agonists. The effects of methoxyfenozide (RH-2485) on growth and reproduction of the Mediterranean flour moth, Ephestia kuehniella Zeller (Lepidoptera: Pyralidae), an important pest in stored products worldwide, were evaluated under laboratory conditions. Topical application on newly emerged pupae induced precocious and lethal adult exuviation. Moreover, it reduced pupal stage duration and inhibited adult exuviation with an LD50 of 0.01 µg/pupa and LD90 of 0.37 µg/pupa. In a follow-up experiment, the adults that survived from treated pupae were investigated for different reproductive event parameters. The treated adults showed a dose-dependent increase in pre-oviposition period, and a decrease in oviposition period and in ovary growth parameters, which in turn resulted in a lower fecundity and egg viability. Typically, the ovaries in treated females contained lower amounts of free ecdysteroids, total protein and lipids, suggesting interference with vitellogenesis.

Seletividade de inseticidas utilizados na cultura algodoeira a ovos e larvas de terceiro instar de Cycloneda sanguinea

Objetivou-se avaliar a seletividade fisiológica de inseticidas utilizados em algodoeiro para ovos e larvas de terceiro instar de Cycloneda sanguinea (Linnaeus, 1763) (Coleoptera: Coccinellidae). Os produtos utilizados em g i.a. L-1 de água foram triflumurom 0,048 (Certero 480 SC), espinosade 0,24 (Tracer 480 SC), clorfenapir 1,2 (Pirate 240 SC), clotianidina 0,33 (Focus 500 PM) e imidaclopride 0,33 + β-ciflutrina 0,042 (Connect 100 + 12,5 SC). Utilizou-se água destilada como tratamento testemunha. Tanto ovos quanto larvas foram distribuídos em placas de Petri e tratados com os inseticidas por meio de pulverização em torre de Potter. O delineamento experimental utilizado foi o inteiramente ao acaso, com cinco repetições e seis tratamentos constituídos pelos cinco inseticidas e pela testemunha, sendo que cada parcela foi composta por dez ovos ou dez larvas de terceiro instar. Avaliaram-se o período embrionário e a viabilidade de ovos tratados; sobrevivência e duração de larvas de terceiro instar; sobrevivência e duração dos estágios de desenvolvimento larval e pupal, razão sexual e o total de ovos colocados pelas fêmeas provenientes de ovos e larvas de terceiro instar tratados. Os bioensaios foram conduzidos a 25 ± 2º C, UR 60 ± 10% e fotofase de 12h. O inseticida triflumurom 0,048 foi seletivo a ovos do predador e levemente nocivo a larvas de terceiro instar. Espinosade 0,24 foi levemente nocivo a ovos e larvas de terceiro instar, e clorfenapir 1,2; clotianidina 0,33 e imidaclopride 0,33 + β-ciflutrina 0,042 foram prejudiciais a ovos e larvas de terceiro instar de C. sanguinea.

Using field-evolved resistance to Cry1F maize in a lepidopteran pest to demonstrate no adverse effects of Cry1F on one of its major predators.

Spodoptera frugiperda (JE Smith) represents the first documented case of field-evolved resistance to a genetically engineered crop expressing an insecticidal protein from Bacillus thuringiensis (Bt). In this case it was Cry1F-expressing maize (Mycogen 2A517). The ladybird beetle, Coleomegilla maculata, is a common and abundant predator that suppresses pest populations in maize and many other cropping systems. Its larvae and adults are polyphagous, feeding on aphids, thrips, lepidopteran eggs and larvae, as well as plant tissues. Thus, C. maculata may be exposed to Bt proteins expressed in genetically engineered crops by several pathways. Using Cry1F-resistant S. frugiperda larvae as prey, we evaluated the potential impact of Cry1F-expressing maize on several fitness parameters of C. maculata over two generations. Using Cry1F resistant prey removed any potential prey-mediated effects. Duration of larval and pupal stages, adult weight and female fecundity of C. maculata were not different when they were fed resistant S. frugiperda larvae reared on either Bt or control maize leaves during both generations. ELISA and insect-sensitive bioassays showed C. maculata were exposed to bioactive Cry1F protein. The insecticidal protein had no effect on C. maculata larvae, even though larvae contained 20–32 ng of Cry1F/g by fresh weight. Over all, our results demonstrated that the Cry1F protein did not affect important fitness parameters of one of S. frugiperda’s major predators and that Cry1F protein did not accumulate but was strongly diluted when transferred during trophic interactions.

Insecticidal activity of different extracts from Scrophularia canina L. against Culex pipiens molestus Forskal (Diptera, Culicidae)

The insecticidal activity of different extracts (aqueous, methyl alcohol, hexane and petroleum ether) of the aerial part of Scrophularia canina against the second and fourth-instar larvae and adult females of Culex pipiens molestus was investigated. The larvicidal activity of all the extracts was tested in the dose range from 7.8 to 1000 ppm. The highest toxicity was exhibited by the petroleum ether extract against second-instar larvae (48 h LC50 = 23.5 ppm) and by the hexane extract against fourth-instar larvae (48 h LC50 = 23.6 ppm). Methyl alcohol and aqueous extracts did not show any larvicidal activity. Sub-lethal doses of petroleum ether and hexane extracts induced increasing mortalities during 13 days after treatment but did not affect the duration of larval and pupal stages. In persistence tests, the hexane extract retained a satisfactory larvicidal activity after a 10-day period of test solutions incubation. Topical treatment of adult females with doses from 0.25 to 8 μg per mg of female body weight of different extracts showed a similar toxicity for the hexane (24 h LD50 = 1.7 μg mg−1) and petroleum ether (24 h LD50 = 1.8 μg mg−1) extracts which were significantly more toxic than methyl alcohol extract (4.2 μg mg−1). Aqueous extract did not induce adult mortality. The marked mosquitocidal activity of petroleum ether and hexane extracts of the aerial part of S. canina against different life stages of C. pipiens molestus is promising to develop effective alternatives to synthetic insecticides.

Pupal Development of <I>Ceratitis capitata</I> (Diptera: Tephritidae) and <I>Diachasmimorpha longicaudata</I> (Hymenoptera: Braconidae) at Different Moisture Values in Four Soil Types

This study aimed to evaluate adult emergence and duration of the pupal stage of the Mediterranean fruit fly, Ceratitis capitata (Wiedemann), and emergence of the fruit fly parasitoid, Diachasmimorpha longicaudata (Ashmead), under different moisture conditions in four soil types, using soil water matric potential. Pupal stage duration in C. capitata was influenced differently for males and females. In females, only soil type affected pupal stage duration, which was longer in a clay soil. In males, pupal stage duration was individually influenced by moisture and soil type, with a reduction in pupal stage duration in a heavy clay soil and in a sandy clay, with longer duration in the clay soil. As matric potential decreased, duration of the pupal stage of C. capitata males increased, regardless of soil type. C. capitata emergence was affected by moisture, regardless of soil type, and was higher in drier soils. The emergence of D. longicaudata adults was individually influenced by soil type and moisture factors, and the number of emerged D. longicaudata adults was three times higher in sandy loam and lower in a heavy clay soil. Always, the number of emerged adults was higher at higher moisture conditions. C. capitata and D. longicaudata pupal development was affected by moisture and soil type, which may facilitate pest sampling and allow release areas for the parasitoid to be defined under field conditions.

Differences in Development, Glycogen, and Lipid Content Associated With Cytochrome P450-Mediated Permethrin Resistance inCulex pipiens quinquefasciatus(Diptera: Culicidae)

Insecticide resistance in populations of mosquitoes is an escalating problem that can directly affect disease prevalence. Determining the fitness associated with an insecticide resistance mechanism (allele) will provide for greater understanding of the evolution of resistance, and help inform effective vector management programs. Previously, a population cage experiment in which the alleles of two highly related strains of Culex pipiens quinquefasciatus (Say) SLAB (susceptible) and ISOP450 (permethrin resistant because of cytochrome P450-mediated detoxification) were placed in direct competition in the absence of insecticide revealed that the P450 resistance allele frequency decreased over time. In the current study, SLAB and ISOP450 development, mortality and energetic resources derived from glycogen, other sugars and lipids were measured to identify biological parameters that might explain the previously observed fitness cost. SLAB exhibited shorter egg-to-adult female development time and larger body size when reared in groups when compared with ISOP450. ISOP450 female adults provided 20% sugar water lived longer than 20% sugar water fed females of the SLAB strain. No significant differences in larval development time, larval mortality, pupal stage duration time, pupal mortality, longevity of male and female adults provided with distilled water and males provided sugar water were found between the strains. The caloric content from glycogen and lipids were significantly higher in SLAB relative to ISOP450 in adults. The slower female emergence time and smaller body size when reared in groups combined with lower energy reserves (glycogen and lipids) associated with the resistance allele (in ISOP450) are likely fitness costs associated with the resistance allele of P450-mediated detoxification.

Differences in Development, Glycogen, and Lipid Content Associated With Cytochrome P450-Mediated Permethrin Resistance in <I>Culex pipiens quinquefasciatus</I> (Diptera: Culicidae)

Insecticide resistance in populations of mosquitoes is an escalating problem that can directly affect disease prevalence. Determining the fitness associated with an insecticide resistance mechanism (allele) will provide for greater understanding of the evolution of resistance, and help inform effective vector management programs. Previously, a population cage experiment in which the alleles of two highly related strains of Culex pipiens quinquefasciatus (Say) SLAB (susceptible) and ISOP450 (permethrin resistant because of cytochrome P450-mediated detoxification) were placed in direct competition in the absence of insecticide revealed that the P450 resistance allele frequency decreased over time. In the current study, SLAB and ISOP450 development, mortality and energetic resources derived from glycogen, other sugars and lipids were measured to identify biological parameters that might explain the previously observed fitness cost. SLAB exhibited shorter egg-to-adult female development time and larger body size when reared in groups when compared with ISOP450. ISOP450 female adults provided 20% sugar water lived longer than 20% sugar water fed females of the SLAB strain. No significant differences in larval development time, larval mortality, pupal stage duration time, pupal mortality, longevity of male and female adults provided with distilled water and males provided sugar water were found between the strains. The caloric content from glycogen and lipids were significantly higher in SLAB relative to ISOP450 in adults. The slower female emergence time and smaller body size when reared in groups combined with lower energy reserves (glycogen and lipids) associated with the resistance allele (in ISOP450) are likely fitness costs associated with the resistance allele of P450-mediated detoxification.

BIOLOGICAL AND BIOCHEMICAL EFFECTS OF TWO PLANT EXTRACTS ON THE BLACK CUTWORM AGROTIS IPSILON (HUFN.)

The biological and biochemical effects of the two plant extracts i.e. lemon and orange peels were studied on the Black Cut Worm (BON) Agrotis ipsllon. For the biological studies, of the second instar larvae were treated by series concentrations of each extract (0.25, 0.50, 1, 2 and 4%). To determine the aspartate aminotransferase (AST), alanine aminotransferase (ALT), total protein and total lipid contents in 4th instar larvae, the 2nd instar larvae were treated with the LC50 concentration of each extract. Results showed that the two tested extracts caused a significant increase in duration of larval and pupal stages. While, induced a significant decrease in the pupation, adult longevity and fertility. Also, the two tested extracts reduced the activity of AST and ALT enzymes and decreased in content both of total protein and total lipid for 4211arval instar.

Effects of temperature on development, survival, longevity, and fecundity of the Bemisia tabaci Gennadius (Homoptera: Aleyrodidae) predator, Axinoscymnus cardilobus (Coleoptera: Coccinellidae)

Axinoscymnus cardilobus (Homoptera: Aleyrodidae) is an important predator of Bemisia tabaci (Coleoptera: Coccinellidae) that occurs in high population density of B. tabaci. Temperature among other factors is observed to play an important role in the development of arthropods. The effect of temperature on the development of A. cardilobus was studied at seven constant temperature regimes (14, 17, 20, 23, 26, 29, 32 °C). The results indicated that the duration of egg, larval and pupal stages were significantly influenced by increased temperature. The rate of development gradually increased with increase in temperature from 14 °C to 26 °C, but declined from 26 °C to 32 °C. The survival rates of different insect stages were stable at temperatures between 20 °C and 26 °C, but at extreme temperatures of 32 °C and 14 °C, a sharp decrease was evident. Ovipositional period of the female decreased when temperatures were increased from 17 °C to 32 °C. The highest fecundity of the female (225.7 eggs per female) was recorded at 23 °C. Life tables of A. cardilobus were constructed based on the experimental results at temperatures of 14–32 °C. The reproductive rate ( R 0), the innate capacity for increase ( r m) and the finite rate of increase ( λ) reached the maximum values at 23 °C, of 70.7, 0.059 and 1.062, respectively. The mean generation time ( T) decreased with increased temperature from 17 °C to 32 °C, the highest and least values recorded at 17 °C and 32 °C were 112.7 and 38.7, respectively. These results offer valuable insight on the importation and establishment of A. cardilobus into new environments with diverse temperature regimes.

Occurrence, biology and behavior of Liogenys fuscus Blanchard (Insecta, Coleoptera, Scarabaeidae) in Aquidauana, Mato Grosso do Sul, Brazil

Due to the importance of some Pleurosticti Scarabaeidae as agricultural pests allied to information absence on the species that occur in Brazilian Central-West region, on studies occurrence, biology and behavior on this group of scarabs were conducted. Biology and behavioral studies started with Liogenys fuscus Blanchard, 1850 (Melolonthinae), a very common species and were developed in Aquidauana, Mato Grosso do Sul. Adult beetles were collected from light traps from February 2005 to January 2007, at the experimental farm of the Universidade Estadual de Mato Grosso do Sul in Aquidauana (UEMS). In the laboratory adults were placed in plastic containers with soil with sprouts of Brachiaria decumbens Stapf (Poaceae). Eggs were transferred to a climatized chamber at 26 ± 1o C with a 12hourlight, 12hour darkness photoperiod cycle. Adult flight activity occurred in August and in September to December from 06:00 pm to 06:00 am, with the largest number of individuals flying from 07:00 to 10:00 pm. Eggs measured 1 x 1.5 mm and were laid individually or in groups in soil chambers; eggs were initially white and became yellow near hatching. The embryonic period lasted 14.3 days; first, second and third instars lasted 28.5, 48.8, and 68.2 days, respectively. The prepupal period lasted 120.2 days and the prepupa stayed inactive in soil. The mean duration of pupal stage was 27.5 days and the mean longevity of adults was 23.6 days. In laboratory the calling behavior between males and females was observed; copulation lasted, in mean, 25 minutes.

Arsenic accumulation, biotransformation and localisation in bertha armyworm moths

Environmental context. Insects play an important role in the impact of environmental pollutants such as arsenic. They may accumulate arsenic to high levels, potentially modifying its chemical form, which affects the insects’ toxicity to predators such as fish and birds. Here we use synchrotron X-ray techniques to determine the distribution and chemical form of arsenic in larva, pupa and adult of the bertha armyworm moth. Abstract. Insects are important in bioaccumulation and dispersal of environmental contaminants such as arsenic, and biotransformation of arsenic to various chemical forms directly impacts its toxicity to insects and to their predators. In a model study, the toxic effects and biotransformation of arsenic were examined in larvae, pupae and adults of bertha armyworm moth (Mamestra configurata Walker) (Lepidoptera: Noctuidae). A synthetic diet containing 100 μM arsenate caused reduced larval survival and increased pupal stage duration but no effect on pupal weight or larval stage duration. Synchrotron X-ray absorption spectroscopy (XAS) showed that larvae biotransformed dietary arsenate to yield predominantly trivalent arsenic coordinated with three aliphatic sulfurs, modelled as AsIII-tris-glutathione. Similar species were found in pupae and adults. XAS imaging with micro X-ray fluorescence imaging revealed highly localised arsenic species, and zinc and copper within the gut. The implication of these arsenic species in the diets of predators is discussed.