Adult Female Longevity Research Articles

Temperature-dependent oviposition model of Scopula subpunctaria (Lepidoptera: Geometridae)

• Temperature significantly influence oviposition S. subpunctaria. • Male adults lived shorter than female did. • The temperature-dependent oviposition model was constructed. Scopula subpunctaria , is one of important defoliating insect pests of tea plants in China. However, the effect of temperature on its longevity and fecundity had not been reported, and the temperature-dependent oviposition model is lacking. The reproductive characteristics of S. subpunctaria were investigated under eight constant temperatures (13, 16, 19, 22, 25, 28, 31, and 33℃), with a 14L: 10D photoperid and 65–85% RH. The results showed that temperature significantly influence oviposition period, longevity, and fecundity of S. subpunctaria . The mean longevity of female adults increased from 10.8 days (33℃) to 33.9 days (13℃). Male lived shorter than female did. The mean longevity of males was shortest at 33℃ (8.1 days) and longest at 23.8℃ (17.6 days). Total fecundity of S. subpunctaria females ranged from 15.4 eggs at 33℃ to 279.9 eggs at 22℃. The temperature-dependent oviposition model of S. subpunctaria was constructed based on four sub-models (developmental rate model, total fecundity model, oviposition rate model, and survival rate model). The results of this study would be helpful in forecasting and predicting population occurrence of S. subpunctaria in tea plantations.

First evidence for thermal tolerance benefits of the bacterial symbiont Cardinium in an invasive whitefly, Bemisia tabaci

Cardinium symbiont is a maternally inherited bacterial endosymbiont and widely spreads in arthropods including Bemisia tabaci (Hemiptera: Aleyrodidae). However, the potential role of Cardinium played in the biology of their hosts is largely unknown. In two genetic lines (i.e. LS and SG lines) of B. tabaci MED, collected from different locations in China, we tested the effects of Cardinium on the performance of the host whitefly under a constant high temperature (31 °C) using the age-stage two-sex life table method, and explored the genes influenced by Cardinium-infection by RNA-sequencing. We found that Cardinium did provide protection of B. tabaci against heat stress under 31 °C. However, there was a significant connection between Cardinium-infection and whitefly genetic backgrounds. Performance revealed that Cardinium infection can increase the longevity of both female and male adults and oviposition periods in both lines, but it also conferred benefits of fecundity and pre-adult period to LS line. Additionally, the population parameters such as intrinsic rate of increase (r), finite rate of increase (λ) and mean generation time (T) demonstrated that Cardinium infection conferred fitness benefits to LS line but not to SG line. Transcriptome analysis indicated that several genes related to homeostasis and metamorphosis such as ubiquitin-related genes were highly expressed in Cardinium-infected B. tabaci. The research provided the first evidence that Cardinium can increase the thermal tolerance of whitefly, which may be associated with host genetic background.

Lethal and sublethal effects of several plant compounds compared to spiromesifen against Tetranychus turkestani

Summary Tetranychus turkestani Ugarov and Nikolski is one of the main agricultural pests of southwestern Iran and some other tropical regions. In the present study, fumigant activity of three essential oils extracted from Rosmarinus officinalis L., Mentha longifolia L. and Eucalyptus globulus Labill., and contact toxicity of two biopesticides (Tondexir and Palizin) on T. turkestani mite females were investigated and compared with that of spiromesifen, a chemical acaricide. Also, sublethal effects of the tested compounds at 50% lethal concentration (LC50) were estimated on the biological parameters of T. turkestani. The LC50 values for E. globulus, R. officinalis and M. longifolia essential oils were 12.50, 11.52 and 4.00 μl/l air and for spiromesifen, Tondexir and Palizin were 10.98, 327.34 and 858.13 ppm, respectively. All tested compounds significantly reduced adult female longevity, equally to the chemical acaricide spiromesifen. Fecundity also decreased in all treatments and this reduction was even higher for plant essential oils than the other compounds. Palizin, E. globulus and M. longifolia significantly reduced the hatchability of T. turkestani eggs similarly to spiromesifen. According to the results, the tested plant compounds are effective against T. turkestani and may be applied as suitable alternatives to synthetic pesticides against this crop pest.

Effect of Different Light-Emitting Diode (LED) Lights on the Behavior and Habits of Scopulasub punctaria Herrichet Schaeffer

To investigate the phototaxis and photophobism behaviors and the gender differences of S. punctaria in response to different light spectra, 18 lights with wavelengths 370–600 nm were used, and effects of green spectrum (520–525 nm) and yellow spectrum (590–595 nm) on the oviposition, hatching rate, eclosion rate and longevity of S. punctaria (indoor fresh leaf-bred for 5 generations) were studied. The results showed that under the light of 370–665 nm, both female and male adults of S. punctaria had the phototropic and photoevasive behaviors (showed multi peaks), with females tended to orange and violet lights (395–400 nm); males tended to amber and violet light (370–375 nm). After 520–525 nm and 590–595 nm light irradiation at night, the number of oviposition decreased by 55.70% and 44% (significant difference); and the hatching rate decreased by 13.33% and 9%, respectively. Both the above two lights have effects on the pre-oviposition and average oviposition period, and have significant effect on the longevity of female adults, while no significant effect on male adults; and both the longevity of female and male adults was prolonged with the increased population density. This study is expected to provide a reference for the research and biocontrol of S. punctaria.

<p class="Body"><strong>Effects of short-term heat stress on the development and reproduction of predatory mite <em>Neoseiulus barkeri</em> (Acari, Phytoseiidae)</strong></p>

The predatory mite Neoseiulus barkeri (Acari: Phytoseiidae), which is one of the best natural enemies, has been used as a biological control agent against multiple insect pests, such as spider mite, Tetranychus urticae and thrips. Its growth and development were affected by the environmental temperature changes. This study was conducted to evaluate the hatching rate of the eggs and the immature developmental times of N. barkeri after incubation of the eggs under heat stress at 38, 40 and 42℃, 85% ± 5% RH and a 16h:8h light: dark (L:D) photoperiod for 2, 4 and 6h. After adult females emerged, they were treated under the same conditions again, and the parameters such as oviposition period, fecundity and female longevity were observed. The results showed that with the increase of the temperature and the extension of the duration of the heat stress, the hatching rate was lower. The eggs treated at 42℃ for 2h or more could not hatch, and the developmental duration of each immature stage showed a trend of decreasing at first and then increasing. The fastest development was observed after incubation of eggs at 40℃ for 2h, and the shortest developmental duration was 4.60d. Under the condition of 38℃, the oviposition period and life span of adult females were shortened with the extension of treatment time, and the fecundity decreased at first and then increased. At 40℃, the fecundity, oviposition period and longevity of adult females showed a trend of gradual increase with the extension of treatment time. The shortest oviposition period, the lowest fecundity and the shortest life span of adult females were 12.14d, 18.92 eggs and 16.65d, respectively after incubation of eggs at 40℃, for 2h. Therefore, the short-term heat stress had a significant effect on the hatching rate and the duration of the immature stage, and also had a negative effect on the fecundity, oviposition period and longevity of adult females. In rearing and field release, heat stress should be avoided as much as possible to achieve the best predation and control effect of N. barkeri.

Biology and Morphometrics of Fall Army Worm Spodoptera Frugiperda (J E Smith) on Maize

The occurrence of fall army worm (FAW) Spodoptera frugiperda (J E Smith) was first reported in India from Shivamogga, Karnataka during May 2018. It was noticed during the survey of maize fields of south Gujarat in September 2018. The present study analyses the biology of FAW on maize under laboratoty conditions with the observations done in the Department of Entomology, N M College of Agriculture, NAU, Navsari. The female laid eggs in clusters on the under or upper surface of the maize leaf, and the incubation period was 2.40± 0.50 days. The larvae passed through six instars with the total larval period of 14.90± 1.47 days. The pupa was observed with/ without earthen cocoon and pupal peiord was 9.30± 0.65 days. The longevity of male and female adults were 7.90± 0.84 and 10.60± 1.22 days, respectively. The sex ratio was female biased (M:F: 1:1.13). The total lifecycle was completed within 34.50± 1.80 days (male) and 37.20± 2.52 days (female). The morphometrics of the life stages are also given.

Biology and Morphometrics of Pulse Beetle, Callosobruchus chinensis (L.) on Chickpea

The biology and morphometrics of pulse beetle, Callosobruchus chinensis were studied on chickpea cultivar ICCV 2 under laboratory conditions at ICRISAT, Patancheru, Telangana, India during 2018-19 and 2019-2020. The experiments were carried out in the BOD incubator at temperature of 28 ± 2ºC and relative humidity of 65 to 70%. The life cycle of C. chinensis included four stages egg, grub, pupae and adult. The data revealed that eggs incubation period in 4-5 days, the grub stage consisted of four instars and its development ranged from 20-25 days, pupation lasted for 6-7 days, whereas, female adult longevity ranged from 9-12 days. The morphometric measurements revealed that the average length and breadth of eggs were 0.62 ± 0.03mm and 0.34 ± 0.02 mm respectively. The length and breadth (mm) of four grub instars G1, G2, G3 and G4 were 0.58 ± 0.02 and 0.30 ± 0.01, 1.53 ± 0.06 and 0.92 ± 0.04, 2.71 ± 0.10 and 1.47 ± 0.06, 3.59 ± 0.14 and 1.96 ± 0.08 respectively. The average length and breadth of pupa were 3.72 ± 0.12 mm, 2.15 ± 0.09 mm. Whereas, the length and breadth (mm) of adult male and female bruchids were 3.87 ± 0.08, 2.07 ± 0.05 and 4.23 ± 0.14, 2.31 ± 0.07 respectively. The total life cycle of C. chinensis ranged from 33-42 days.

Biological and behavioural characteristics of Diaeretiella rapae (McIntosh), a parasitoid of Lipaphis erysimi (Kaltenbach) infesting oilseed brassicas in India

ABSTRACT Biological and behavioural characteristics of Diaeretiella rapae were studied in a laboratory using Lipaphis erysimi as a host. The total developmental period of the parasitoid was longer in early instars as compared to that in later instars. Host age at the time of oviposition affected the oviposition period, post-oviposition period and fecundity of the parasitoid. Survival of the immatures was higher in older than the younger instars. The sex ratio for the parasitoid was found to be female-biased. Adult longevity of D. rapae was longer for females when compared to that of males. The mean longevity of adult females of the parasitoid was longer while parasitizing nymphs of younger age groups (1–2 days) compared to that of older age groups (4–5 days). L. erysimi reared on mustard was found to be the best host for D. rapae based on high parasitisation (%), female-biased sex ratio and the shortest time required by the parasitoid for completion of the total developmental period. The parasitoid showed a higher preference towards second instar nymphs of L. erysimi, both in choice and no-choice tests. The per capita parasitisation and search efficiency of the parasitoid decreased with an increase in parasitoid density. Logistic regression exhibited type-II functional response for the parasitoid D. rapae. Overall, D. rapae appeared to be a potential biocontrol agent of L. erysimi that would supplement its biological control in oilseed brassicas.

Influence of cold-storage of eggs of Menochilus sexmaculatus (Coleoptera: Coccinellidae) on the biology and predatory efficiency

The ladybird Menochilus sexmaculatus is an important natural predator with potentially broad applications in agriculture and forestry ecosystems. We evaluated the effects of different low-temperature treatments on the biological characteristics of M. sexmaculatus, by investigating its growth and development after exposure of the eggs to 4 °C, 8 °C, and 12 °C for 3 days using an experimental population life-table method. The survival rates of 1st-instar larvae of M. sexmaculatus were significantly lower at 4 °C and 8 °C (0.71 ± 0.03 and 0.79 ± 0.02, respectively) compared with those of larvae exposed to 12 °C and 26 °C. Furthermore, the developmental period of the immatures was significantly shorter at lower temperatures compared with at 26 °C. Fecundity examination showed that the pre-oviposition period was significantly prolonged after exposure to 4 °C and 8 °C (7.27 ± 0.38 and 6.50 ± 0.29 days, respectively) compared with 12 °C (5.46 ± 0.49 days) and 26 °C (5.13 ± 0.35 days). Furthermore, the oviposition period and oviposition at 4 °C and 8 °C were significantly reduced compared with those at 12 °C and 26 °C. The longevity of both male and female adults was also significantly shorter when exposed to 4 °C and 8 °C. There was no significant difference between the predation functions of M. sexmaculatus after exposure to 12 °C and 26 °C. These results indicated that the biological characteristics and prey performance of M. sexmaculatus were significantly affected by low temperatures. However, apart from hatchability, the other main biological characteristics and prey performance were similar after 12 °C cold-treatment to those at normal temperature (26 °C), suggesting that 12 °C may be an ideal temperature for storing M. sexmaculatus eggs.

Biting rhythm and demographic attributes of Aedes albopictus (Skuse) females from different urbanized settings in Penang Island, Malaysia under uncontrolled laboratory conditions.

Urbanization could potentially modify Aedes albopictus’ ecology by changing the dynamics of the species, and affecting their breeding sites due to environmental changes, and thus contribute to dengue outbreaks. Thus, this study was conducted to evaluate the biting rhythm, fecundity and longevity of adult female Ae. albopictus in relation to urbanization strata; urban, suburban and rural areas in Penang Island, Malaysia. The experiments were done in comparison to a laboratory strain. Twenty-four hours biting activity of all the mosquito strains showed a clear bimodal biting activity, with morning and evening twilight peaks. The interaction effect between biting time and mosquito strains was not significant. Meanwhile, differences in fecundity among mosquito strains were statistically significant (F(3,442) = 10.559, P < 0.05) with urban areas having higher mean number of eggs (mean = 107.69, standard error = 3.98) than suburban (mean = 94.48, standard error = 5.18), and rural areas (mean = 72.52, standard error = 3.87). Longevity of adult females were significantly higher (F(3,441) = 31.259, P < 0.05) for mosquito strains from urban areas compared to the other strains. These findings would provide crucial information for the planning of control programs in Malaysia, particularly Penang.

Lead stress affects the reproduction of Spodoptera litura but not by regulating the vitellogenin gene promoter

Lead (Pb) stress affects hormone-mediated responses (e.g., reproduction) in insects. In this study, the effects of Pb stress (12.5–50 mg Pb/kg in larval artificial diets) on the reproduction of the common cutworm Spodoptera litura (Lepidoptera: Noctuidae) were investigated after 7 generations. The results showed that Pb stress did not reduce the longevity of adult females, but 50 mg Pb/kg significantly reduced the longevity of adult males, regardless of the generation. After 50 mg Pb/kg stress for one or 7 generations, the peak time of egg-laying was delayed, and egg production and hatchability were decreased significantly. The vitellin content in eggs was significantly inhibited by Pb stress. The S. litura vitellogenin (Vg) gene promoter was cloned and analyzed. Multiple putative transcription factors were predicted for the 2321 bp Vg promoter region, including the TATA box, GATA, basic helix-loop-helix (bHLH) transcription factor, Broad-Complex (BR-C) binding sites, etc. The fragment from −2222 to −211 bp of the Vg promoter was the activation domain for Vg, whereas the region from −211 to −55 bp repressed the activity of the Vg promoter. The construct promoter (−782/+76) in Trichoplusia ni (Hi5) cells significantly improved Vg expression, which was not affected by Pb stress (1 or 10 mg/ml). Therefore, Pb stress significantly inhibited the reproduction of S. litura but not by regulating the Vg promoter.

&lt;p class="Body"&gt;&lt;strong&gt;Oviposition model of &lt;em&gt;Amblyseius swirskii&lt;/em&gt; Athias-Henriot in prey system (&lt;em&gt;Tetranychus urticae&lt;/em&gt; Koch)&lt;/strong&gt;&lt;/p&gt;

In this study, temperature-dependent oviposition model of Amblyseius swirskii Athias-Henriot fed by Tetranychus urticae Koch as prey was developed. In order to obtain data for the model, the longevity, fecundity and survivorship of adult females of A. swirskii were recorded at seven different temperatures (15, 20, 25, 27.5, 30, 32.5 and 35 °C) all at 60±5% RH and a photoperiod of 16:8h (L; D) in growth chamber. The longevity of females decreased with increasing temperature; the maximum at 15°C (84±3.24 days) and the minimum at 32.5°C (22.48±0.31 days). The female adult developmental rates (1/median longevity) was described by Sharpe and DeMichele model (r2=0.99). The highest and the lowest fecundity were observed at 25°C (22.63±0.76 eggs/female) and 15°C (9.4±0.67 eggs/female), respectively. The oviposition model comprised of three functions: temperature-dependent fecundity, age-specific cumulative oviposition rate and age-specific survival rate. The best model of temperature-dependent fecundity was described by a non-linear equation (extreme value function) (r2=0.98). Similarly, the best model of age-specific cumulative oviposition was described by the two-parameter Weibull function (r2=0.94). Eventually, the best model of age-specific survival rate was described by sigmoid function (r2=0.97). Amblyseius swirskii has ability to control pests such as thrips, whiteflies and two-spotted spider mites and can grow even in low temperatures. Therefore, this mite can be active at the beginning of spring season. Temperature-dependent oviposition model of A. swirskii can determine optimal temperature for mass-rearing and predict seasonal population dynamic of this predatory mite in greenhouses. Finally, the greenhouse data can validate this model in future.

Host dependent demographic parameters of spider mite Oligonychus biharensis (Hirst) on two bean species

The influence of two economic host plants country bean (Lablab purpureus L.) and mung bean (Vigna radiata (L. Wilczek)) on the development, reproduction and demographic parameters of the spider mite, Oligonychus biharensis (Acari Tetranychidae) were constructed using two-sex life table program under laboratory condition at 25 °C, 60–80% RH, and a photoperiod of 16 L:8D h. Both male and female of O. biharensis successfully completed their development from egg to adult on two host plants. Immature development of O. biharensis was shorter on L. purpureus than on V. radiata. Oviposition, lifetime fecundity, female adult longevity of the spider mite was higher on L. purpureus than V. radiata. The net reproduction rate (R0), intrinsic rate of natural increase (rm), mean generation time (tG), finite rate of increase (λ) and gross reproduction rate (GRR) of O. biharensis were significantly affected by host plants. The R0-values of O. biharensis were significantly higher on L. purpureus than V. radiata. GRR also showed the similar trend as of the net reproduction rate. The mean generation time of O. biharensis was higher on V. radiata than on L. purpureus. Based on the intrinsic rate of population increase, L. purpureus was more suitable than V. radiata. The results of the study reveal that the host plants greatly influenced the life parameters of the spider mite O. biharensis and it helps to reveal the population dynamics on particular host plant species.

Developmental biology of Platygaster diplosisae Risbec and Aprostocetus procerae Risbec

Platygaster diplosisae (Risbec, 1956) and Aprostocetus procerae (Risbec, 1956) are ovo-larval and pupal parasitoids, respectively of Orseolia oryzivora (H & G). The reproductive biology of the two parasitoids was studied by authors, but their developmental biology was not yet explored. Mature rice galls due to O. oryzivora were collected from irrigated rice fields of Karfiguela and Boulbi, located in Western and Central Burkina Faso respectively. They were kept in wooden cages (45.5 cm × 44.7 cm × 59.5 cm) or plastic buckets (32 cm × 29 cm) covered with a fine mesh mosquito net to prevent insects from escaping after emergence. Fourteen-day rice plants of the variety FKR 28 were infested by adults of O. oryzivora in two metal cages (1.52 m × 1.26 m 1.65 m) (10 pairs of adults for each cage). In this way, it was possible to maintain a continuous culture of O. oryzivora that allowed the mass rearing of the parasitoids. The studied biological parameters of the parasitoids included, duration of post-embryonic development, lifespan, fecundity and fertility. The results revealed that the development time of A. procerae from egg to adult was 28 ± 6.18 days and that of P. diplosisae 33 ± 6.94 days. The mean incubation time of P. diplosisae eggs was 16 ± 1.98 days and that of A. procerae was 3.2 ± 1.78 days. Each of the two parasitoids exhibited three stages of larval development. The mean durations of the three larval stages of A. procerae were 5 ± 2.78, 3 ± 1.14 and 3 ± 0.55 days, respectively. For P. diplosisae, these figures were 2.2 ± 0.54 and 3 ± 0,71 days respectively. The pupal development time of P. diplosisae was 10 ± 2.26 days while that of A. procerae was 15 ± 3.92 days. The average number of ovarian eggs of the female of P. diplosisae was 213 ± 32.34 while the average number of parasitoid eggs inside the larva of O. oryzivora was 106 ± 18.43. The average number of ovarian eggs of A. procerae was 11 ± 2.93. The lifespan of adult females of A. procerae (15 ± 3.64 days) fed with honey was longer than that of males (7 ± 4.77 days) fed under the same conditions. Male’s longevity was significantly different from that of the female depending on food and temperature. Longevity of honey-fed adult females of P. diplosisae (6 ± 3.31 days) was longer than that of honey-fed adult males (3 ± 0.55 days). The life span of unfed adult females (3 ± 0.71 days) as well as that of unfed adult males (1 ± 0.15 day) were shorter. The results obtained from the two parasitoids associated with Orseolia oryzivora could be used for the development of a biological control of Orseolia oryzivora.

Factors Affecting the Reproduction and Mass-Rearing of Sclerodermus brevicornis (Hymenoptera: Bethylidae), a Natural Enemy of Exotic Flat-Faced Longhorn Beetles (Coleoptera: Cerambycidae: Lamiinae).

Simple SummaryNatural enemies play a fundamental role in the control of invasive insects and may be particularly important in controlling Xylopagous beetle, which are difficult to contain with traditional chemicals as they are usually concealed within wood. Among the natural enemies that have proven effective against these beetles are parasitoid species in the genus Sclerodermus. The present article furthers knowledge of Sclerodermus brevicornis performance, focusing on the survival capability under different thermal conditions and the longer-term influences of these conditions.Many species of long-horned beetles are invasive pests causing significant economic damage in agro-forestry systems. They spend the majority of their life-cycle concealed inside natural wood or wooden packaging materials and are largely protected from adverse environmental conditions and pesticide sprays. Biological control via parasitoid natural enemies including members of the bethylid genus Sclerodermus, has proven effective against some long-horned beetles that are invasive in China. In Europe, the biocontrol potential of native Sclerodermus species is being evaluated with a view to developing efficient mass-rearing techniques and then actively deploying them against invasive Asian beetles. Here, we continue evaluations of S. brevicornis by establishing that groups of females that have already reared offspring to emergence are capable of reproducing subsequent hosts and by evaluating the lifetime reproductive capacity of individual females provided with successive hosts. Additionally, we assess the laboratory shelf-life of adult females stored for different times at different temperatures including cold storage, and then assess the post-storage reproductive performance of groups of females provided with a single host. We found that adult female longevity declines with increasing storage temperature and that most aspects of subsequent performance are negatively affected by high temperatures. The adaptability to low temperature storage enhances the suitability of S. brevicornis to mass-rearing programs and thus biocontrol deployment.

Demography of Thrips palmi (Thysanoptera: Thripidae) Reared on Brassica oleracea (Brassicales: Brassicaceae) and Phaseolus vulgaris (Fabales: Fabaceae) With Discussion on the Application of the Bootstrap Technique in Life Table Research.

In order to contrast the fitness of Thrips palmi Karny reared on two of its hosts plants, Brassica oleracea L. leaves and Phaseolus vulgaris L. beans, life tables were constructed for T. palmi individuals reared on the two hostplants at 25°C using the age-stage, two-sex life table. The durations of the egg, first instar larva, pupa, and total immature stages of T. palmi reared on P. vulgaris were significantly longer than those reared on B. oleracea, whereas the adult preoviposition period, female adult longevity, and number of oviposition days of T. palmi reared on B. oleracea were significantly longer/greater than those on P. vulgaris. The fecundity (F) of T. palmi reared on B. oleracea (159.71 offspring/female) was significantly higher than in females reared on P. vulgaris (F = 122.98 offspring/female) despite the higher proportion of female adults that emerged on P. vulgaris. Although there were no significant differences in the intrinsic rate of increase (r), finite rate (λ), net reproductive rate (R0), and mean generation time (T) between the two populations, computer projection showed that the T. palmi population will increase faster when reared on B. oleracea than on P. vulgaris. Our results demonstrate that population projection based on life table data is potentially an important tool in pest management. Furthermore, we used the bootstrap technique to demonstrate the variable effect that survival rate and fecundity at different ages can have on population parameters.

English

In the present work, laboratory and field strains of the greater wax moth, Galleria mellonella L. (Lepdoptera: Pyralidae) were reared on two food types (artificial diet for laboratory strain and wax frames for field strain) to study some biological aspects of the developmental stages of braconid wasp, Apanteles galleriae Wilkinson (Hymenoptera: Braconidae) the parasitoid of G. mellonella. Results of total developmental period, percentages of adults&rsquo; emergence and longevity of females of the parasitoid are different when reared on two strains of G. mellonella. Total developmental period of the immature stages was shorter on field strain (47.26 days) than that reared on laboratory strain of G. mellonella recording 57.5 days. In contrast, no significant differences were observed between the longevity of adult females reared on the two strains, where the longevity period was 25.33 and 26.3 days in laboratory and field strains, respectively.&nbsp; Also, life cycle of immature stages, longevity of adults and reproductive parameters of the parasitoid A. galleriae were determined. The fecundity of A. galleria decreased when reared on laboratory strain of G. mellonella; it was 140 progeny/females and increased to 177.3 progeny/females when A. galleria was reared on G. mellonella field strain. On the other hand, the sex ratio of the parasitoid and longevity are different between the two strains. Results of the life tables for G. mellonella and the parasitoid, A. galleria strains, showed shortage in generation periods for that reared on the field strain. The present study was conducted to explore the effect of food types on some biological parameters of G. mellonella and its parasitoid, A. galleria. Key words: Parasitoid, greater wax moth, biology, life table, host preference. &nbsp

Life history and temperature-dependence of cassava-colonising populations of Bemisia tabaci

The whiteflies belonging to the species group Bemisia tabaci transmit viruses that are the greatest constraint to the production of cassava, Africa’s most important food security crop. We studied the life history of an endemic African population of B. tabaci SSA-ESA at six constant temperatures (16, 20, 24, 28, 32, 36 °C) in controlled environment chambers, and for 10 generations in the field. Oviposition occurred between 20 and 28 °C, with highest fecundity (114.5 ± 88.2) eggs per female at 20 °C. Similarly, B. tabaci adult females average survival time was longest (19.7 days) at 24 °C, and shortest (8.5 days) at 36 °C. Immature development time decreased with increasing temperature from 59.3 days at 16 °C to 16.3 days at 28 °C, and increased above 28 °C. A constant temperature of 36 °C was lethal to eggs and first instars and no immature stage developed further to adults at this temperature. Several temperature-driven models were fitted for describing the species development, survival and reproduction using Insect Life Cycle Modelling (ILCYM®) software. Median temperature-dependent development rates in individual immature life stages were statistically described by Taylor, Briere 1 and Tb (Logan) models. Temperature-dependent mortality and senescence rates in immature stages were described by using parabolic nonlinear models. The longevity of adult females and oviposition time was best described by the Weibull distribution. Maximum population growth was predicted between 26 and 28 °C. These results will be useful for spatio-temporal analysis of climate change impacts on the distribution and abundance of this pest.

The biology and ecology of pine aphid, Eulachnus tuberculostemmatus (Hemiptera: Aphididae) and its demographic responses to environmental changes

Abstract Eulachnus tuberculostemmatus (Hemiptera: Aphididae) is the most abundant aphid species attacking pine trees in Isfahan, Iran. Population fluctuations of this species and its natural enemies were studied on Pinus brutia var. eldarica by weekly sampling. Its fertility‐life table parameters were determined in the field in spring and summer 2016. Furthermore, effects of different temperatures (15, 20, 25, and 30 °C) and irrigation regimens (well irrigated, moderately and highly drought‐stressed) on its performance were investigated in the laboratory. The aphid population reached its peak abundance between 11 April and 23 May. Also, a minor peak was observed between mid‐November and mid‐December. During the survey, no sexual morphs were observed. Most fertility‐life table parameters of E. tuberculostemmatus were found to be significantly higher in spring than in summer. Aphids reared at 20 and 25 °C had a significantly higher net reproductive rate, intrinsic rate of increase and finite capacity for increase compared to those reared at 15 and 30 °C. Also, the aphid performed significantly better on highly drought‐stressed trees, due to higher survival rate, female adult longevity and fecundity. Population peaks of the four Coccinellidae predators Adalia bipunctata, Hippodamia variegata, Propylea quatuordecimpunctata and Coccinella septempunctata coincided with that of the aphid.

Survival and Fecundity of Antilochus coquebertii (Hemiptera: Pyrrhocoridae) on Different Stages of Dysdercus koenigii (Hemiptera: Pyrrhocoridae)

The red cotton bug, Dysdercus koenigii F. (Hemiptera: Pyrrhocoridae) is a destructive pest of cotton in the cotton belt region of Pakistan. This pest attacks the cotton bolls, mature cotton seeds and causes serious damage to premature bolls. A trial was conducted under laboratory conditions to check the predatory potential of A. coquebertii on different stages of D. koenigii. Four stages of D. koenigii i.e. 3rd, 4th, 5th nymphal instars and adults were provided to A. coquebertii adults to check their survival, fecundity response and feeding potential. Results were statistically significant when comparing feeding preferences of A. coquebertii on different stages of D. koenigii. Adult male and female longevity of A. coquebertii was significantly higher when these insects were fed with 3rd instar nymphs of D. koenigii, which was 115.25 ± 6.91 and 88.75 ± 4.64 days, respectively. Maximum egg laying percentage of 34% was recorded on medium 3 and minimum egg laying percentage of 16% was recorded on medium 2. Based on the results of this study, survival and fecundity rate of A. coquebertii can be highly affected when the suitable stage of D. koenigii is not present.