Cardinium Localization During Its Parasitoid Wasp Host’s Development Provides Insights Into Cytoplasmic Incompatibility

Arthropods harbor heritable intracellular symbionts that may manipulate host reproduction to favor symbiont transmission. In cytoplasmic incompatibility (CI), the symbiont sabotages the reproduction of infected males such that high levels of offspring mortality result when they mate with uninfected females. In crosses with infected males and infected females, however (the “rescue” cross), normal numbers of offspring are produced. A common CI-inducing symbiont, Cardinium hertigii, causes variable levels of CI mortality in the parasitoid wasp, Encarsia suzannae. Previous work correlated CI-induced mortality with male development time in this system, although the timing of Cardinium CI-induction and the relationship between development time and CI mortality was not well understood. Here, using a combination of crosses, manipulation of development time, and fluorescence microscopy, we identify the localization and the timing of the CI-induction step in the Cardinium-E. suzannae system. Antibiotic treatment of adult Cardinium-infected males did not reduce the mortality associated with the CI phenotype, suggesting that CI-alteration occurs prior to adulthood. Our results suggest that the alteration step occurs during the pupal period, and is limited by the duration of pupal development: 1) Encarsia produces most sperm prior to adulthood, 2) FISH localization of Cardinium in testes showed an association with sperm nuclei throughout spermatogenesis but not with mature sperm, and 3) two methods of prolonging the pupal period (cool temperatures and the juvenile hormone analog methoprene) both caused greater CI mortality, suggesting the degree of alteration is limited by the duration of the pupal stage. Based on these results, we compare two models for potential mechanisms of Cardinium sperm modification in the context of what is known about analogous mechanisms of Wolbachia, a more extensively studied CI-inducing symbiont.

Biorational Management of Pulse Beetle (Callosobruchus chinensis L.) in Gram Seed

The pulse beetle, Callosobruchus chinensis is one of the major pests in stored pulse causes 40-50% losses of pulses in storage. Experiments were conducted to study the efficacy of some selected biorational insecticides on percent mortality of beetle, percent weight loss of seeds, no. of eggs laid per female, percent hatchability, larval duration, pupal period and adult longevity of pulse beetle, Callosobruchus chinensis under laboratory condition. Among the different botanicals, neem oil (77%) was found the most effective showing 78% mortality of pulse beetle in direct method followed by Mahogany oil (69%) and karanja oil (62%). In case of indirect method, the highest percent mortality was recorded from karanja oil (37%) which was followed by Neem oil (33%) and Mahogany oil (33%). Among different microbial derivatives, Libsen was found most effective considering mortality followed by Suspend 5SG and Ambush 1.8EC. The highest percentage of weight reduction was observed in Karanja oil (15%) and the lowest (14%) was in Mahogany oil. The highest percentage of weight reduction was obtained from Ambush 1.8EC (16%) and the lowest percentage of weight reduction was obtained from Suspend 5SG (13%). No. of eggs laid per female was the highest in mahogany oil (24) and lowest in Libsen (19). Percent of hatchability was highest in mahogany oil (21%) and lowest in Libsen (16%). Larval duration was the highest in mahogany oil (16 days) and the lowest was in Suspend 5SG(13days). Pupal period highest in neem oil (7 days) and the lowest was in (6 days). The highest adult longevity (22 days) from the seeds treated with karanja oil. The lowest adult longevity (18 days) from seeds treated with Libson. Thus, Karanja, Neem and Mahogany oil, Libsen, Ambush 1.8EC and Suspend 5SG were found effective against pulse beetle in storage. Therefore, these biorationals might be included in the development of IPM packages for the management of pulse beetle in the storage.

BIONOMICS OF THE JUTE YELLOW MITE, POLYPHAGOTARSONEMUS LATUS (BANKS) (ACARI: TARSONEMIDAE) IN JUTE (CORCHORUS OLITORIUS L.) AT DIFFERENT TEMPERATURE-HUMIDITY

The jute yellow mite Polyphagotarsonemus latus constitutes one of the major pests of jute crop in Bangladesh. The objective of this work was to study the biology of the P.latus, to determine its temperature-humidity responces in jute (Corchorus olitorius L.) var. O-9897. Bionomics of jute yellow mite, Polyphagotarsonemus laenerationtus (Banks) were studied in the laboratory of Bangladesh Jute Research Institute during March 2013 to September 2013. The incubation period of yellow mite on the variety O-9897 was 1.95 days for female and 1.90 days for male; larval period of 1.00 days for female, 0.75 days for male ; pupal period of 0.70 days for female and 0.71 days for male ; egg-adult period of 3.65 days for female and 3.44 days for male were highest in the 1st generation with 25.55±0.15oC and 56±1.47% relative humidity among three generations. pre-oviposition and oviposition period was o.65 days and 12.25 days. The highest longevity 13.45 days for female and 8.50 days for male. The daily mean of eggs were 2.20, 1.91 and 1.75 eggs in three successive generations. The number of eggs laid per female in her life time was 28.6, 24.8 and 12.2 eggs.

Aspects of the biology of Ephestia cautella and Tribolium castaneum on fermented stored cocoa beans

Ephestia cautella (Walker) (Lepidotera: Pyralidae) and Tribolium castaneum (Herbst) (Coleoptera: Tenebrionidae) are pests associated with dried fermented stored cocoa beans that cause extensive damage. The biology of these pests on cocoa beans in Ghana has not been well documented, especially on T. castaneum. Due to climate changes and improved/hybrid seedlings being released to farmers, it has become necessary to re-evaluate the biology and damage of these pests on fermented stored cocoa beans. The experiments were conducted in the Insectary laboratory of the Department of Crop and Soil Sciences, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana. Paired 0-1 day old E. cautella adults were placed in Petri dishes and covered with Kilner jars. The eggs laid daily by each female were carefully transferred onto 15 g cocoa beans in Petri dishes. The egg incubation period was four days, 31 days larval period and the pupal period of seven days. Unmated adult males lived for 12.1 days and females 7.9; mated males lived for 10.9 days and females 5.5. Paired T. castaneum were introduced on 2.0 g broken cocoa beans in Petri dishes. The average incubation period was nine days, 40 days larval period, and pupal period of five days.

Susceptibility of different stored pulses infested by pulse beetle, Callosobruchus chinensis (Lin.)

The susceptibility of different stored pulses infested by Callosobruchus chinensis L. (Coleoptera: Bruchidae) was observed in three varieties of stored pulses i.e. gram (Cicer arietnum L.), pea (Pisum sativum L.) and mung (Vigna radiata L.) during April, 2017 to May, 2018. The longest incubation-, larval- and pupal period of pulse beetle were in gram 5.4 ± 0.29, 12.6 ± 0.25, 5.5 ± 0.32 days, respectively and the shortest were in mung 4.6 ± 0.25, 11.3 ± 0.28, 4.2 ± 0.19 days, respectively. The shortest developmental period of pulse beetle was 20.1 ± 0.46 days in mung. The incubation-, larval-, pupal- and total developmental period of pulse beetle varied significantly between the pulse beetle grown in gram and mung (p < 0.05). The highest longevity and fecundity were in gram, 8.2 ± 0.33 days and 70.2 ± 7.53, respectively. The fecundity did not vary significantly in different stored pulses (p > 0.05). The longevity and number of adults emerged varied significantly (p < 0.05) between the gram and pea. The number of male emerged did not vary significantly (p > 0.05) between the different stored pulses and the number of female emerged varied significantly (p < 0.05) between gram and pea, pea and mung. The experiment revealed that pulse beetle preferred smooth coated and large size seeds to oviposit. Pea was found to be most resistant to attack by C. chinensis L. whereas mung was more susceptible than gram and pea. Dhaka Univ. J. Biol. Sci. 29(1): 19-25, 2020 (January)

Effects of Pre-Diapause Temperature and Body Weight on the Diapause Intensity of the Overwintering Generation of Bactrocera minax (Diptera: Tephritidae)

The Chinese citrus fruit fly, Bactrocera minax (Enderlein), is an economically important pest of citrus. The fly has an obligatory pupal diapause in soil from November to March. However, techniques for predicting or determining the emergence of the adult have, thus far, not been well documented. In this study, we investigated the effects of different pre-diapause temperatures (8, 12, 16, and 20°C) and pupal body weight (five groups according to pupal weight: G-58, 55.0–61.0 mg; G-68, 65–71 mg; G-78, 75–81 mg; G-88, 85–91 mg; G-95, 92–98 mg) on pupal period (the indicator of diapause intensity). The pupal period of B. minax larvae pupated at 8°C was 193.41 d, which was significantly shorter than that of larvae incubated at higher temperatures, suggesting that there was a lower diapause intensity for larvae pupated at lower pre-diapause temperatures. There were also significant differences in the pupal periods at different pupal body weights. The pupal period of G-58 was significantly shorter than that of the heavier groups (G-88 and G-95), and the pupal period increased with increasing pupal body weight in the five groups. Moreover, the pupal period of B. minax significantly and positively correlated to pupal body weight. These findings demonstrate that the pre-diapause temperature and pupal body weight are suitable indicators for predicting the pupal period of overwintering individuals, and the results of this study will contribute to the development of new and effective strategies for predicting the occurrence and population dynamics of B. minax adult.

Nest Structure, Development and Natural Enemies of Ceratina hieroglyphica Smith, A Stem Nesting Bee Colonizing Cashew Trees in Hilly Terrains

Ceratina hieroglyphica nesting sites were located in dried tiny twigs of cashew trees, and the life stages were observed through periodical collection of nests. Nests were located in the pithy region up to a maximum of 20 cm deep, and individual cells of 3.5 4 mm were separated by partitions. In 2017, one hundred and two nests were collected, of which twenty-two had been abandoned. Older cells were at the bottom of nests, while young ones towards the entrance. Among the different stages, the most in the nests were adults (51.8%), followed by pupal stages. Periodical collection of nests and the observations on developmental stages of the bees indicated that the nesting period was found to occur between October and March. Each egg was laid on a pollen provision located in separate cells and the incubation period lasted for 3.1±0.29 days. The larval period and pupal period lasted for 8.4±0.63 days and 7.3±01.41 days, respectively. Adults survived up to fourteen days in lab conditions with 10% honey solution. Parasitoids, predators and pathogens recorded on this bee species are also presented here.

Comparative Biology of Pink Bollworm, Pectinophora gossypiella Saund. on Bt. and Non-Bt. Cotton

Effect of Bt. and non-Bt. cotton variety was investigated on biological parameters of pink bollworm Pectinophora gossypiella. In biological parameters, maximum larval duration of 4.5±0.07 days were recorded in the first instar on non-Bt. cotton and minimum 2.00±0.06 days in fourth larval instar on Bt. cotton. The larval weight was higher (20.24±1.74 mg) on non-Bt. and minimum on Bt. cotton (13.84±1.34 mg); meanwhile the maximum pupal weight of 23.46±0.55 mg was weighed on non-Bt. cotton and minimum 17.41±0.44 mg on Bt. cotton. A total period of 18.44±0.55 day’s adult female lived on non-Bt. cotton and15.44±0.43 on Bt. cotton. The overall maximum mean numbers of 119±1.99 eggs were observed on non-Bt. cotton as compared to Bt. cotton. Similarly, ovipositional rate was also higher (8.04±0.19 eggs/ female/day) on non-Bt. cotton. The maximum larval duration (11.36±0.30 days) was higher on non-Bt. cotton and minimum on Bt. cotton (8.03±0.43 days); meanwhile the maximum pupal period of 9.73±0.29 days were calculated on Bt. cotton and almost similar days of pupal period on non-Bt. cotton crop, respectively. The highest mortality percentage of all stages was found on Bt. cotton with maximum mortality percentage of 24.59% at 1st larval instar.

Biology of Danaus chrysippus L. (Lepidoptera: Danaidae): feeding potentials in the larval host plants and adult nectar plants

The biology and feeding potential of plain tiger butterfly, Danaus chrysippus L. (Lepidoptera: Danaidae) were examined in both field and laboratory conditions from July 2011 to June 2012. Field collected singly laid eggs on host plant (Asclepias curassavica) were reared in the laboratory at room temperature (25 ± 3 °C) and 70 ± 5% RH. Various life stages of the butterfly, viz. egg, larvae, pre-pupa, pupa and adult have been described. The egg incubation period was 4.6 ± 0.8 days; the duration of larval stages from 1st to 5th instars were 1.7 ± 0.2, 2.2 ± 0.2, 2.5 ± 0.3, 2.7 ± 0.2 and 3.1 ± 0.4 days, respectively; pre-pupal period was 1.4 ± 0.4 days; pupal period was 8.6 ± 1.1 days; the longevity of the adult females was 7.8 ± 0.3 days and of the males was 10.4 ± 0.7 days. The larval lengths of each of the five instars were 3.7 ± 0.84, 8.7 ± 1.09, 14.3 ± 1.20, 23.2 ± 2.36 and 38.5 ± 2.54 mm, respectively. The feeding potential rates of the five instar larvae were 5.5 ± 1.11%, 22.8 ± 2.96%, 67.7 ± 2.99%, 96.8 ± 4.09% and 293.6 ± 15.9%, respectively. The weights (in gram) of the excreta of five larval instars were 0.06 ± 0.02, 0.13 ± 0.03, 0.54 ± 0.06, 0.81 ± 0.06 and 1.96 ± 0.09, respectively. A total of 187 individuals was observed on 16 potential nectar plants in the Butterfly Research Park (BRP), Gazipur. These were Lantana camara, Asclepias curassavica, Duranta plumeri, Hibicus rosa sinensis, Duranta repens, Tagetes patula, Ixora chinensis, Heliotropium indicum, Cosmos bipinnatus, Wedelia calendulaca, Punica hybrida, Spilanthes calva, Leucas linifolia, Helianthus annus, Euphorbia pulcherrima and Gomphera globosa. Among these, L. camara was visited most frequently (16.58%) and L. linifolia was least frequently (1.60%) by this butterfly. No Danaus chrysippus was observed visiting H. annus and E. pulcherrima plants. J. Biodivers. Conserv. Bioresour. Manag. 2019, 5(1): 121-132

Effects of cold exposure on Tenebrio molitor (Coleoptera: Tenebrionidae) pupal period, proportion of adult emergence, weight and deformation percentage

Low temperatures affect many life history traits of insects. The purpose of this study was to assess the effects of duration of cold exposure on the length of Tenebrio molitor’s pupal period, proportion of adult emergence, adult weight and proportion of deformed adults. The trials were conducted in a laboratory in constant conditions with wheat flour and whole-wheat flour meal were used as food. Cold-exposed groups were achieved by exposing pupae taken on the first day after pupation for 1, 3, 5, 10 and 15 days at +4 °C. The results showed that as the period of cold increased, pupal period extended and proportion of deformed adults increased whereas there were no or less straightforward effects on adult weights and proportion of emerged adults, respectively