Mean Development Time Research Articles

Determination of Biology and Prey Preference of the Predator Insect, Xylocoris flavipes (Reuter) (Heteroptera: Anthocoridae) Against Storage Pests

This study was carried out to determine the biology of Xylocoris flavipes Reuter (Heteroptera: Anthocoridae), an important predator of stored product pests, and its prey preference on some warehouse pests. The study was conducted under laboratory conditions at 25±2ºC temperature and 55±10% humidity. Ephestia kuehniella Zeller (Lepidoptera: Pyralidae) eggs were used to determine the biology of X. flavipes. E. kuehniella, Tribolium confusum Jacquelin du Val (Coleoptera: Tenebrionidae), and Trogoderma granarium Everts (Coleoptera: Dermestidae) larvae were utilized to detect the prey preferences of X. flavipes. The mean development time (days) of five nymphs, female and male adults of Xylocoris flavipes on E. kuehniella eggs were as follows: 4.2±0.63; 3.1±0.57; 2.9±0.57; 3.0±0.00; 4.5±0.53; 104.2±17.01; 114.6±12.34, respectively. The average egg consumption for the aforementioned stages was: 5.0±1.76; 9.9±3.07; 9.1±6.01; 13.3±4.14; 22.5±4.79; 515.6±75.46; 286.2±24.39, respectively. Although mature male X. flavipes survived longer than females, females consumed more E. kuehniella eggs than males. The mean oviposition period of the females was 36.7±12.39 days, and the average laid egg number was 117.3±29.86. The consumed E. kuehniella eggs and larvae, T. confusum, and T. granarium larvae during the predator nymph period were on average 63.1±6.01; 49.6±2.76; 26.8±3,52; 12.8±4.29, respectively. The average development time (days) of the nymphs for the aforementioned consumption stages were 16.4±1.96; 15.4±0.52; 16.2±1.14; 21.6±4.62, respectively. The consumed E. kuehniella eggs and larvae, T. confusum, and T. granarium larvae during the predator adult period were on average 570±231.32; 249.5±142.10; 218.1±110.57; 22.2±6.23, respectively. The average development time (days) of the adults for the aforementioned consumption stages were 87.5±30.92; 75.9±41.18; 89.3±43.55; 24.5±7.18 days, respectively. X. flavipes preferred mostly E. kuehniella eggs among the preys during the nymph and adult stages, and least T. granarium larvae.

Off-season survival and life history of beet armyworm, Spodoptera exigua (Hubner) on various host plants

The beet armyworm, Spodoptera exigua (Hubner) (Lepidoptera: Noctuidae), has become a significant pest of chickpea in recent years. The polyphagous nature allows it to survive on various hosts during the off-season, creating a great menace to the crop in the following season. To assess the incidence and document the alternate hosts of S. exigua, a rapid roving survey was conducted in 11 chickpea-growing areas of Prakasam district, Andhra Pradesh, India. Additionally, the life history traits of S. exigua were studied on major alternate host plants under laboratory conditions (27 ± 1 °C and 70 ± 2% RH) to understand the survival, life expectancy and potential contribution to future populations. The results show that, among the different crops surveyed, the maximum larval incidence was noticed in maize (1.93 larvae/plant), cowpea (1.73 larvae/plant), and sunflower (1.68 larvae/plant) during the off-season. Life history studies of S. exigua showed that highest larval survival percentage was observed on chickpea (83.6%), while the lowest was on maize (44.5%). The mean developmental time for larvae was longest on maize (27.1 days) and shortest on chickpea (14.9 days). Larvae did not develop beyond the third instar when fed with chilli. The growth index statistics showed chickpea (9.2) was the most suitable host plant, whereas maize (0.9) was the least suitable host. The age-stage-specific survival rate (Sxj) varied across developmental stages, and the survival curves overlapped, indicating different growth rates among individuals. The life expectancy (exj) at age zero was highest on groundnut (37.06 days). The intrinsic rate of increase (r) of S. exigua was lowest on maize (0.10 ± 0.0013) and highest on chickpea (0.22 ± 0.0010). Similarly, the net reproductive rate (R0) was highest on chickpea (846.39 ± 18.22) and lowest on maize (59.50 ± 2.06). The population doubled every 3.08 ± 0.011 days on chickpea compared to 7.22 ± 0.80 days on maize. The study conclusively indicates that chickpea and sunflower, primarily cultivated during the rabi season in India, are the most preferred hosts for S. exigua. In contrast, maize and cotton, mainly grown during the kharif season, are less preferred and merely support the pest's survival. Consequently, S. exigua switches hosts between different crops growing seasons, so effective management of S. exigua during the kharif season can help prevent pest outbreaks during the rabi season.

Biology of <i>Diachasmimorpha longicaudata</i> (Hymenoptera: Braconidae) Reared on Third Instar Larvae of <i>Bactrocera dorsalis</i> (Diptera: Tephritidae)

The biology of Diachasmimorpha longicaudata (Ashmead) was studied on third instar larvae of Bactrocera dorsalis (Hendel) to optimize its mass rearing in the laboratory. The mean parasitoid emergence rate ranged from 55–92% during its first 13 days of life. The number of females was higher than that of males. The mean development time from egg to adult emergence was 20.14± 0.02 days in females and 17.72± 0.02 days in males. Fed females lived longer than fed males. Food-deprived females and males lived 72 hr after emergence. The lifespan of males and females was 16.42± 0.53 and 15.86± 0.35 days, respectively, in pairs exposed to B. dorsalis larvae.

Life history of the two predacious mites species, Amblyseius swirskii, and Neoseiulus cucumeris (Acari: Phytoseiidae), as biological control agents of the date palm mite, Oligonychus afrasiaticus (Acari: Tetranychidae).

The date palm mite, Oligonychus afrasiaticus (McGregor) (Acari: Tetranychidae), is a serious pest of dates in the Middle East and North Africa, inflicting severe economic damage if not controlled early. As predaceous mites are known to be potential biocontrol agents against several pests, so predation capacity, life table, reproduction, and survival of Amblyseius swirskii Athias-Henriot and Neoseiulus cucumeris (Oudemans) (Acari: Phytoseiidae), collected from date palm farms in Qassim Saudi Arabia, were studied under laboratory conditions (25 °C, 30 °C, 35 °C and 50 ± 5% RH) against all motile stages of O. afrasiaticus. For both predators, mean developmental time, oviposition period, and longevity were inversely related to temperature from 25 to 35 °C. Various parameters were studied for A. swirskii and N. cucumeris at 25 °C, 30 °C and 35 °C, i.e. the female developmental time, 9.37, 7.29, 5.56, and 10.67, 8.38, 6.45 d; oviposition period, 19.77, 16.18, 13.94 and 15.90, 13.84, 10.64 d; longevity, 29.39, 24.79, 20.64 and 25.42, 21.94, 17.39 d; fecundity, 31.91, 37.10, 42.16 and 21.75, 26.84, 30.56 eggs per female, respectively. The maximum daily predation rate for both the predators was recorded at 35 °C during the oviposition period. The total predation of A. swirskii and N. cucumeris female was 370.86, 387.54, 405.83, 232.14, 263.32, 248.85 preys at 25 °C, 30 °C and 35 °C respectively. The maximum reproduction rate of A. swirskii and N. cucumeris (3.02, 2.87 eggs/♀/day) was recorded at 35 °C while the minimum (2.00, 1.36 eggs/♀/day) was recorded at 25 °C. The life table parameters were estimated as net reproductive rate (Ro) 21.68, 25.94, 29.52 and 18.95, 20.25, 22.78; the mean generation time (T) 24.92, 21.82, 18.24 and 26.30, 23.60, 20.56 d; the intrinsic rate of increase (rm) 0.181, 0.232, 0.248 and 0.170, 0.185, 0.196; the finite rate of increase (λ) 1.365, 1.551, 1.706 and 1.126, 1.324, 1.428 for A. swirskii and N. cucumeris at 25 °C, 30 °C and 35 °C respectively. The results of this study suggested that the two phytoseiid species are promising biological control agents of O. afrasiaticus at a wide range of temperatures.

Temperature dependent development of black soldier fly, Hermetia illucens (L.) (Diptera: Stratiomyidae) from Yangtze River Delta region of China

The black soldier fly, Hermetia illucens (L.) (Diptera: Stratiomyidae), isomnivorous andwidely distributed in the world. Black soldier flies usually colonize corpse at a relatively late stage and have a longer developmental time compared to other flies. It can serve as a good supplementary indicator for estimating a longer minimum postmortem interval (PMImin) in forensic investigations. In this paper, the development of H. illucens was investigated at six constant temperatures between 19 and 34 °C. Under temperatures of 19, 22, 25, 28, 31, and 34 °C, the mean developmental time from eggs to adults was 90.96, 58.29, 54.61, 42.33, 32.33 and 34.52 days, respectively. Developmental time and accumulated degree days results were used to construct thermal summation model and isomorphen diagram. The calculated values of lower developmental thresholds and thermal summation constant estimated by a linear model were 11.88 °C and 650.89 degree days, respectively. Through a nonlinear model, the upper lethal developmental threshold temperature, intrinsic optimum temperature and lower developmental thresholds were estimated to be 35.18, 20.50 and 13.17 °C, respectively. A growth curve, an equation and isomegalen diagram based on them show the relationship between developmental time and larval body length. The larval body length increased with increased developmental time and eventually plateaued, revealing an S-shape growth curve. These results provide important basic developmental data for H. illucens, which can be used to estimate the PMImin.

Developmental Indicators of Chrysomya nigripes Aubertin under Different Constant Temperature Conditions and an Application Case for Estimating the PMImin.

Chrysomya nigripes Aubertin, 1932, is a Calliphoridae species that colonize the carcass after the bloat phase and remains for long periods. Some early sarcosaprophagous insects complete one generation of development and are no longer associated with the corpse and surrounding environment, while C. nigripes larvae and pupae remain, providing a basis for the estimation of the minimum postmortem interval (PMImin) for highly decomposed or skeletonized carcasses. However, data on the growth and development of this species are not yet complete. As a result, we studied the developmental patterns of C. nigripes at eight constant temperatures ranging from 16-37 °C and constructed various developmental models, including the isomorphen diagram, isomegalen diagram, linear thermal summation model, nonlinear thermodynamic Optim SSI model, and logistic regression model. Chrysomya nigripes could not complete the entire developmental process at 16 °C, although it could be completed at other temperatures. The mean developmental times (±SD) of C. nigripes from egg to adult at 19 °C, 22 °C, 25 °C, 28 °C, 31 °C, 34 °C, and 37 °C were 644.9 ± 36.8 h, 422.9 ± 20.1 h, 323.1 ± 13.9 h, 246.6 ± 11.2 h, 202.5 ± 1.8 h, 191.5 ± 3.8 h, and 191.8 ± 2.0 h, respectively. The thermal summation constant (K) and lower critical thermal threshold (TL) derived from the linear thermal summation models were 4083.00 ± 293.39 degree hours and 12.52 ± 0.83 °C, respectively. In addition, TL, intrinsic optimum temperature (TΦ), and upper critical thermal threshold (TH) estimated by the optimized nonlinear thermodynamic Optim SSI model were 15.76 °C, 24.88 °C, and 38.15 °C, respectively. This study provides more comprehensive developmental data of C. nigripes for PMImin estimation.

Understanding In Vitro Embryo Development through Classical Germination Measurements: A Case Study of Dragon’s Blood (Croton lechleri Müll Arg.)

Sample size fluctuation and the restriction of measurements that demonstrate kinetics (typical of physiological processes) are two of the largest inferential constraints in studies on embryonic development in vitro. Thus, we hypothesize that a practical and robust way of aggregating knowledge on aspects of embryonic development in vitro is to use measurements based on the binary counting component. These are typically used to measure the germination process (intraeminal embryonal development). Our biological model was Dragon’s blood (Croton lechleri Müll Arg.), a species native to the Amazon with great socioeconomic impact. Matrices originating from two populations (one native and another cultivated) were the source of biological material. From this material, we studied five sampling densities (5, 25, 50, and 100 embryos), forming a 2 × 4 factorial ANOVA. Among the measurements studied, the coefficient of variation of time, uncertainty, and the synchronization index were the most sensitive to sample-size fluctuation. The synchronization index, however, also proved to be an interesting measurement to detect the parental effect related to the place of occurrence of the matrices. The embryonic development ability, mean development time, and mean development rate were not affected by fluctuations in the sample size or the origin of the material, demonstrating highly conserved traits of the species. Finally, in general, the measurements based on binary counting demonstrated robustness for modeling embryonic growth.

Biology and Ecology of Delia planipalpis (Stein) (Diptera: Anthomyiidae), an Emerging Pest of Broccoli in Mexico.

Delia planipalpis (Stein) (Diptera: Anthomyiidae) is a pest of crucifers, such as broccoli, radish, cauliflower, turnip and cabbage. It has been recently described in Mexico as a significant emerging pest of broccoli. Due the lack of knowledge of this pest, the present study aimed to determine its life cycle, female sexual maturation, copulation, oviposition behavior and adult longevity. The identity of the fly in Mexico was confirmed genetically by sequencing the cytochrome oxidase subunit 1 gene (COI). The mean development time of D. planipalpis was 32-33 days on radish at 24 °C under laboratory conditions. Females became sexually mature 1-2 days after emergence, and the highest incidence of matings was recorded on the second day (60%). Under choice conditions, D. planipalpis females preferred to oviposit on radish plants, rather than broccoli plants, possibly due to the use of radish for rearing the laboratory colony. Oviposition and the mean number of eggs laid varied among the broccoli varieties, with the highest oviposition observed on the Tlaloc variety. Repeated attempts to rear the laboratory colony on broccoli plants failed. Radish-reared insects of both sexes lived longer when individualized in the adult stage (14.5-22.5 days) than when adult flies were maintained in groups (10-11 days). This study contributes to the understanding of D. planipalpis biology and provides information that can be used to establish future control strategies against this pest.

LIFE TABLE ATTRIBUTES AND FEEDING EFFICIENCY OF OENOPIA SAUZETI (MULSANT) (COLEOPTERA: COCCINELLIDAE) FED ON APHID (APHIS GOSSYPII)

Ladybird beetles are play vital role in agroecosystem due to successful and efficient feeding behavior against aphids, the present research experiment was carried to find out the life history and feeding efficacy of oenopiasauzetifed on Aphis gossypii,at the laboratory of Biological Control, integrated pest management programme (IPMP), National Agriculture Research Centre (NARC), Islamabad. The results of the experiment revealed that the mean developmental time of immature stage 3rd and 4th instar have a significant difference with 3.72±0.11 and 3.87±0.036 days, while the egg to adult emergence was 39±0.35 days. The longevity has significant difference in male and female with the higher values at female 34.0 days. Similarly, the feeding efficiency was maximum in O. sauzeti females which feeds on 2227.1 mean number of Aphis gossypii, while the (409.25±1.42) mean numbers of aphids were consumed by larva. The maximum aphid consumption was observed at 4th instar larva (198.98±0.51 aphid) followed by 3rd instar larva (128.57±0.59 aphid). The mean oviposition time of O. sauzetion A. gossypii was recorded as 21.36 days and average eggs laid female-1 day-1 was 20.53, while the total laid eggs given by a female were 253.60. The apparent mortality (100qx) was maximum at egg stage (24) and the mortality survival ratio (MSR) was highest at pupal stage (0.53), similarly, the indispensable mortality (IM) was also observed high at pupal stage. The maximum survival fraction (Sx) was observed at the 4th larval stage (0.91) and the maximum life expectancy (ex) was observed at 1st larval instar (4.51) days. The total killer power (k-value) of the O. sauzetifor the complete generation was 0.49. This will help to develop an ecofriendly managing approach for the minimizing the aphids infestationin economical important crops.

Life cycle of Melittobia acasta (Hymenoptera: Eulophidae) using Megachile rotundata (Hymenoptera: Megachilidae) as a host

Abstract Megachile rotundata F. is the primary commercial pollinator for alfalfa seed production in North America. Managed M. rotundata populations are susceptible to several mortality factors including attack by parasitoids. One such parasitoid, Melittobia acasta Walker, is a multivoltine wasp whose infestations can decimate bee stocks. Details of M. acasta life history using M. rotundata as a host are needed to develop control strategies. Our objectives were (i) to describe the M. acasta life cycle using M. rotundata prepupae as hosts and (ii) to determine the M. acasta developmental base temperature and propose a degree-day model. First, 150–300 M. acasta adults were introduced to 60 M. rotundata prepupae (10–20 wasp females/4 bee prepupae) upon which they oviposited. Progeny development (at 30 °C) was monitored through adulthood. We identified 12 distinct phases of the M. acasta life cycle that were observed among samples over an average of 19.5 days. Second, vials each containing a M. rotundata prepupa with M. acasta eggs were positioned across a temperature gradient bar (2 vials per temperature). In repeated trials, wasp development was tracked from egg to adult where a mean development time for 30 °C was found to be 13 days. A linear regression analysis determined the lower developmental temperature threshold to be 8.55 °C. Application of this base temperature in a degree-day model revealed an average of 305.8-degree-day accumulation from egg to adult. These results provide a framework to assist bee managers in devising M. acasta control strategies and timing their implementation.

Biology and life table of Tetranychus neocaledonicus André (1933) (Acari: Tetranychidae) in different hosts

Tetranychus neocaledonicus colonizes both cultivated and spontaneous plants. Species such as Phaseolus lunatus, Vigna unguiculata, Abelmoschus esculentus, and Glycine max are listed as hosts to T. neocaledonicus. However, very little is known about the bioecological aspects of this host-T. neocaledonicus interaction. The present study aims to determine the biological aspects (development and survival of immature individuals, reproduction, and fertility life table parameters) of T. neocaledonicus in P. lunatus, V. unguiculata, A. esculentus, and G. max. Individuals of T. neocaledonicus multiplied in laboratory were used on plants of P. lunatus to establish the experiments. To evaluate biological and reproductive parameters, three daily assessments were performed during the immature stages and one assessment during the adult stage. The mean developmental time from egg to adult was recorded. The highest mean was observed in V. unguiculata (13.57 days). Tetranychus neocaledonicus showed the highest fecundity in V. unguiculata, G. max and P. lunatus: 93.75, 93.38, and 79.10 eggs/female and longevity of 43.78, 33.42, and 47.26 days, respectively. Survival rate was above 50% until the 50th day in P. lunatus, 65th day in G. max and V. unguiculata, and 40th day in A. esculentus. The hosts G. max and V. unguiculata provided the highest net reproduction rates (R0) for T. neocaledonicus. The intrinsic rate of increase rm was lower when mites parasitized V. unguiculata and A. esculentus. This also happened for the finite rate of increase (λ). Host plants affect the performance and the biological, population, and reproductive parameters of T. neocaledonicus. Glycine max is the most favorable host for the development and reproduction of T. neocaledonicus.

Hadronotus pubescens (Motschoulsky) (Hymenoptera, Scelionidae): Redescription, biological attributes, and parasitism on eggs of Riptortus pedestris (Fab.) (Hemiptera, Alydidae)

Riptortus pedestris (Fab.) (Hemiptera, Alydidae) is one of the most damaging insects of leguminous crops in Eastern Asia but has only recently emerged as a pest in Bangladesh. Eggs, nymphs and adults of R. pedestris are here reported from mung bean (Vigna radiata (L.)) fields in Bangladesh. Two parasitoid species were reared from field-collected eggs of R. pedestris, the solitary Hadronotus pubescens (Motschoulsky) (Hymenoptera, Scelionidae) and a gregarious species of Ooencyrtus Ashmead (Hymenoptera, Encyrtidae). Here we redescribe H. pubescens, treat H. hogenakalensis (Sharma) as a junior synonym, and report aspects of its biology that were investigated under laboratory conditions. The number of eggs parasitized by H. pubescens was constant with eggs up to 48 hours in age, decreasing by 14% for 96 hour-old eggs. As host egg age increased, the parasitoid mean development time increased and the longevity of the parasitoids decreased.

Association between Temperature and Reproductive Fitness of Diaphorina citri Infected with Candidatus Liberibacter Asiaticus

Diaphorina citri is a serious insect pest of citrus and an insect vector of Candidatus Liberibacter asiaticus (CLas) that causes Huanglongbing disease (citrus greening). In this study, we investigated the effect of the CLas pathogen on the life history parameters of D. citri at different temperature regimes. Our results demonstrated that the survival rate of first to fifth instar CLas-positive and CLas-negative D. citri fluctuate with the change in temperature over the range of 16–35 °C. Meanwhile, the mean developmental time (52.5 d) (d = day(s)) and adult longevity (5.2 d) of the CLas-positive psyllids was longer as compared to CLas-negative psyllids mean developmental time (32.81 d) and adult longevity (3.50 d) at the low- and high-temperature regimes (16 and 35 °C). However, at high temperature regimes, the significant effect of CLas-bacteria on D. citri fecundity was higher than the corresponding non-significant effect on their survivorship when compared to non-vectored psyllids. These results indicate a long-term, stable evolutionary relationship among vector-pathogen and climate change.

3.5-GHz radiofrequency electromagnetic radiation promotes the development of Drosophila melanogaster

With the rapidly increasing popularity of 5G mobile technology, the effect of radiofrequency radiation on human health has caused public concern. This study explores the effects of a simulated 3.5 GHz radiofrequency electromagnetic radiation (RF-EMF) environment on the development and microbiome of flies under intensities of 0.1 W/m2, 1 W/m2 and 10 W/m2. We found that the pupation percentages in the first 3 days and eclosion rate in the first 2 days were increased under exposure to RF-EMF, and the mean development time was shortened. In a study on third-instar larvae, the expression levels of the heat shock protein genes hsp22, hsp26 and hsp70 and humoral immune system genes AttC, TotC and TotA were all significantly increased. In the oxidative stress system, DuoX gene expression was decreased, sod2 and cat gene expression levels were increased, and SOD and CAT enzyme activity also showed a significant increase. According to the 16S rDNA results, the diversity and species abundance of the microbial community decreased significantly, and according to the functional prediction analysis, the genera Acetobacter and Lactobacillus were significantly increased. In conclusion, 3.5 GHz RF-EMF may enhance thermal stress, oxidative stress and humoral immunity, cause changes in the microbial community, and regulate the insulin/TOR and ecdysteroid signalling pathways to promote fly development.

Some Biological Parameters of Caryedon furcatus (Anton & Delobel) (Coleoptera: Chrysomelidae), Developing on the Seeds of Senegalia macrostachya (Reichenb. ex DC.) Kyal. & Boatwr. (Fabales: Mimosaceae), an Edible Wild Legume in Burkina Faso

The beetle Caryedon furcatus (Coleoptera: Chrysomelidae) attacks and destroys the seeds of Senegalia macrostachya (Fabales: Mimosaceae), thereby limiting their availability as food throughout the year. Very few studies have focused on the ability of this pest to develop on S. macrostachya seeds. The objective of this study was to determine some bio-demographic parameters of C. furcatus on the seeds of S. macrostachya. The results of this study showed that the peak of female oviposition occurs on the second day after emergence. The female laid during her lifetime, an average of 37 eggs of which an average of 35 hatched, while larval survival until imago was 87.14 %. The weight and size of emerged adults did not differ statistically by sex. However, the sex ratio was female-biased. The mean development time for C. furcatus to complete its development on the seeds of S. macrostachya was 50 days. With a population that doubles every 4.75 days, C. furcatus could cause significant damage to the seed stocks of S. macrostachya.

Life cycle, population parameters, and predation rate of the hover fly Eupeodes corollae fed on the aphid Myzus persicae

AbstractTo improve the effectiveness of biological control procedures, it is necessary to quantify the survival rate of a natural enemy through the various stages of the life cycle, the fecundity rate, and the predation rate from birth to death. It is not only important to obtain all the parameters associated with a life table, but also to quantify the predation rate in the life table framework. For this purpose, the life history, population parameters, and predation rate of Eupeodes corollae (Fabricius) (Diptera: Syrphidae) were determined using Myzus persicae (Sulzer) (Hemiptera: Aphididae) as prey and the age‐stage, two‐sex life table methods. As predators released in biocontrol programs are mass‐produced from small populations with a consequent loss of genetic variability, we used specimens from a laboratory colony with similar characteristics. The highest mortality was found in the egg stage (54%). The mean developmental time of the pre‐adult stage was 13.70 ± 0.08 days. In the adult stage, the mean longevity was 23.81 ± 1.14 days, with the males living longer than the females. The total pre‐oviposition period was 17.62 ± 0.45 days and the mean female fecundity was 169.81 ± 29.65 eggs per female. The population parameters indicated that the population grew with a net reproduction rate of 32.87 ± 7.25 offspring per individual and an average generation time of 23.05 ± 0.65 days. The values related to the number of aphid nymphs consumed by the larvae were: a mean predation rate (cxj) of 485.20 ± 11.61 nymphs, a net predation rate (C0) of 216.68 ± 16.89, and a finite predation rate (ω) of 28.03 ± 1.18. The obtained results support the use of E. corollae as valuable resource in the biological control of aphids, specifically M. persicae. Moreover, the technique implemented in this paper allows the objective comparison of E. corollae capacity as control agent with that of other aphidophagous hover fly species and other aphid natural enemies.

Temperature-dependent phenology of the parasitoid Fopius arisanus on the host Bactrocera dorsalis.

Fopius arisanus (Sonan), an egg-pupal parasitoid of numerous fruit fly species, was recently introduced into Africa for the control of the Oriental fruit fly, Bactrocera dorsalis (Hendel). In this study, life-table data of F. arisanus were generated under laboratory conditions at six constant temperatures (15, 20, 25, 30, 28 and 35°C; 75% RH, L12:D12 photoperiod) and under variable conditions in a screenhouse on B. dorsalis. Several non-linear functions were fitted to model species development, mortality, longevity and oviposition using the Insect Life Cycle Modeling (ILCYM) software. The established phenology models were stochastically simulated at variable temperatures to estimate the life table parameters. Fopius arisanus completed development from egg to adult at all the temperatures tested except at 35°C. Mean developmental time from egg to adult was inversely proportional to the temperature. The minimum temperature threshold (Tmin) from egg to adult was 8.15°C, while the maximum temperature threshold (Tmax) was estimated at 34.2°C. The optimal temperature for immature stages survival was predicted for 20-30°C. The optimum fecundity estimated was 251 eggs/female at 22°C. Following the stochastic simulations under natural conditions of the selected agro-ecological zones, it appears that the Humid Forest with Bimodal Rainfall provides a suitable thermal condition for potential population growth of F. arisanus. The present study shows the importance of temperature on the demographic parameters of F. arisanus. Implications of present findings on the biological control of B. dorsalis under climate change scenarios is discussed.

Ocean warming is projected to speed development and decrease survival of crab larvae

Increasing mean ocean temperatures, due to climate change, are recognized as one of the biggest threats to marine ecosystems and the goods and services they provide. The vulnerability of an organism to climate change can be projected as a function of sensitivity and exposure during growth. These projections have becoming increasingly necessary to improve ecosystem and resource management. We estimate how ocean warming will impact crab populations of commercial interest on the tropical and subtropical Atlantic coast. A compile of laboratory data was used to estimate the temperature dependence of survival and development for Ucides cordatus and Menippe nodifrons. A decrease in mean survival probability and mean development time, under ocean warming scenarios through 2100 are projected. Lower survival probabilities and development time were projected for lower latitudes compared to higher latitudes. Increasing temperatures along the Atlantic coast will likely impact larval settlement with consequences for population maintenance and connectivity among populations. As indirect consequences, ecological and economic disturbances are expected.

Transgenerational effect of insecticides on juvenile development time of the Sweetpotato whitefly parasitoid Eretmocerus mundus Mercet (Hymenoptera: Aphelinidae)

Eretmocerus mundus Mercet (Hymenoptera: Aphelinidae) is a highly efficient parasitoid that has been commercially used for augmentative biological control of the sweetpotato whitefly Bemisia tabaci Gennadius (Hemiptera: Aleyrodidae). The success of control efforts with this parasitoid could be compromised by the use of non-selective pesticides. This study was conducted to determine if acetamiprid, imidacloprid, thiamethoxam, spinetoram, and sulfoxaflor had transgenerational effects on juvenile development of E. mundus. The mean development time from oviposition (OVP) to first sign of parasitism (FSP) for progeny of females treated with control was 9.03 days, which was the shortest compared to the insecticide treatments. After FSP, the control groups reached their pre-pupal (PP) stage in an average time of 3.85 days, while it was in the range of 3.98–4.46 days for insecticide-treated groups. The developmental period from pre-pupal to black-eyed pupal stage ranged from 2.32–2.69 days for parasitoids treated with insecticides, but it was 2.22 days for the control group. The overall mean development time—from oviposition until adult emergence—was 16.24 days for control, which was statistically shorter than all other treatments. Spinerotam and sulfoxaflor prolonged immature development by 2.37 and 1.83 days, respectively, when compared with the control. Male development was slightly shorter than that of female in control, spinetoram, and sulfoxaflor groups, and the opposite was true for the neonicotinoids. Compared to the neonicotinoids, the non-neonicotinoids had more negative effect on juvenile development of E. mundus.

Characterization of life-history parameters of an Anopheles funestus (Diptera: Culicidae) laboratory strain.

The colonization of the African malaria vector Anopheles funestus has been hampered by inadequate knowledge of its mating and development under laboratory conditions. Life-tables are routinely used to provide baseline biological characteristics needed for colonization. This study characterized age-specific life-table attributes of an existing An. funestus laboratory strain to gain insight into factors that are critical for its colonization. To achieve this, the An. funestus laboratory strain was reared from eggs to adulthood under standard insectary conditions, monitoring and characterizing each developmental stage. The mean insemination rate of females was 74.8% with an average egg load of 67.1 eggs/female and a mean fertility of 86.7%. The mean developmental time from 1st instar larvae (L1) to pupation was 16.4 days. The mean proportion of L1 that survived to pupation was 72.9%. On average, 78.8% of the pupae successfully eclosed as adults. The median longevity for adult males and females was 44 and 28 days, respectively. This work constitutes the first report on life-table characterization of an An. funestus strain. The larval developmental time was within the range reported for wild An. funestus while adult longevity was higher compared to survivorship observed in wild populations. These data demonstrate that the colonized An. funestus strain has potential to be re-colonized under standard insectary conditions. The study provides base-line information for further studies on identifying critical parameters for the maintenance of An. funestus under artificial conditions.