Flying males mediate oviposition and migration in female Mythimna separata (Lepidoptera: Noctuidae)

In recent decades, the oriental armyworm, Mythimna separata (Walker), has caused severe damage to staple grains in China. However, little is known about when M. separata begin their first migration and the role of males in reproduction and migration. Here, the migratory benefits and reproductive costs of flight frequency were examined in adults under laboratory conditions. We found that flying males had a positive effect on ovarian and reproductive development in females who flew for 1–2 nights by comparing two treatment groups (flying and nonflying male groups). Moreover, flying males decreased the flight capacity and flight propensity of females. In contrast, flight for more than two nights by males significantly inhibited ovarian and reproductive development in adult females. Compared with the controls (0 night), male flight for 1–2 nights significantly shortened the preoviposition period but significantly increased ovarian and reproductive development in females. However, male flight for more than three nights significantly inhibited female reproduction and flight capacity. These results indicate that M. separata begin their first migration within 2 days after emergence and fly for two nights. Prolonged flight times can result in significant reproductive costs. Females initiated their first migration earlier than males due to a stronger flight capacity. These observed findings will be useful for forecasting and monitoring population dynamics to prevent outbreaks of M. separata and reduce crop losses.

Strength surpasses relatedness–queen larva selection in honeybees

Nepotism was initially theoretically predicted and sometimes found to trigger the selection of specific larvae to be reared as queens in the honeybee Apis mellifera. Although the importance of selecting the next queen for a colony indicates that it should not occur at random, nepotism is increasingly considered unlikely in eusocial insect societies. Different prenatal maternal supplies of embryos have been found to impact fitness in many other species and therefore could be a possible trigger underlying the likelihood of being raised as a queen. We offered related or unrelated larvae from six colonies originating from eggs of different weights for emergency queen rearing in queenless units with worker bees from these six colonies. We showed that nurses did not significantly prefer related larvae during queen rearing, which confirms the theory that different relatedness-driven kin preferences within a colony cannot be converted into a colony-level decision. However, we found that larvae originating from heavier eggs were significantly preferred for queen breeding. Studies on other species have shown that superior maternal supply is important for later reproductive success. However, we did observe tendencies in the expected direction (e.g., queens that hatched from heavier eggs had both more ovarioles and a shorter preoviposition period). Nevertheless, our data do not allow for a significant conclusion that the selection of larvae from heavy eggs truly offers fitness advantages.

Toxicity, Sublethal and Low Dose Effects of Imidacloprid and Deltamethrin on the Aphidophagous Predator Ceratomegilla undecimnotata (Coleoptera: Coccinellidae)

Ceratomegilla undecimnotata (Coleoptera: Coccinellidae) is a common aphidophagous coccinellid predator used in biological control against aphid pests. Knowing toxicity, lethal, and sublethal effects of insecticides on natural enemies is essential in order to incorporate them into Integrated Pest Management (IPM). In the present study, the lethal and sublethal effects of imidacloprid and deltamethrin were evaluated on the fourth instar larvae of C. undecimnotata and subsequently on the full life cycle. Our results strongly suggest that sublethal and low doses of imidacloprid and deltamethrin at LD10 and LD30 affected fourth instar larvae duration time, adult preoviposition period, total preoviposition period, and fecundity. Moreover, the intrinsic (r) and finite (λ) rate of increase and the net reproduction rate (R0) significantly decreased in populations treated with imidacloprid compared to the control population. The data clearly suggest that imidacloprid and deltamethrin have a negative influence on population growth parameters of C. undecimnotata at sublethal and low doses and, therefore, these insecticides should be used with caution within the context of IPM.

A Comparison of Fitness-Related Traits in the Coleopteran Parasitoid Dastarcus helophoroides (Coleoptera: Bothrideridae) Reared on Two Factitious Hosts

The coleopteran parasitoid Dastarcus helophoroides (Fairmaire) (Coleoptera: Bothrideridae) is considered an efficient preventative method against the damage caused by a large number of cerambycid pests in China and other East Asian countries. Mass rearing of this parasitoid depends on screening appropriate factitious hosts. In this paper, the fitness-related traits of this parasitic beetle were explored using pupae of the two tenebrionid beetles, Tenebrio molitor Linnaeus and Zophobas morio Fabricius (Coleoptera: Tenebrionidae) as factitious hosts. The results showed that in dual-choice trials, D. helophoroides larvae preferred to attack Z. morio pupae. In no-choice trials, D. helophoroides reared on Z. morio pupae displayed significantly higher pupation and emergence rate, longer developmental duration of larval and larval–pupal stages, larger adult body size, shorter preoviposition period, more egg masses and egg production, and higher relative expected reproduction than those reared on T. molitor pupae. These results demonstrate that Z. morio is a more suitable factitious host for mass rearing of D. helophoroides.

The Population Growth of Spodoptera frugiperda on Six Cash Crop Species and Implications for Its Occurrence and Damage Potential in China

Spodoptera frugiperda is a significant migratory invasive pest, identified as a serious threat to agricultural production and food security in China. However, to our knowledge, the effects of most host plants on the biological characteristics of S. frugiperda have not been well studied. To develop effective management strategies for S. frugiperda in its new invasive habitat, basic biological and ecological knowledge of this pest are crucial requirements. Here, we examined the effects of six cash crops maize, wheat, soybean, tomato, cotton and Chinese cabbage on the development, survival, fecundity of S. frugiperda by using the age-stage, two-sex life table. The preadult stage, adult preoviposition period and total preoviposition period of S. frugiperda were shortest on maize and wheat but were longest on tomato. Fecundity was greatest on maize and wheat but smallest on tomato. The highest intrinsic rate of increase, finite rate of increase, net reproductive rate and the shortest mean generation time were recorded on maize. This present study showed that S. frugiperda could cause great economic losses to these cash crops, which should attract the attention of agricultural management departments. Our findings provide useful information in predicting population dynamics and understanding the potential damage that could be incurred by S. frugiperda invasion.

Effects of Temperature on the Development and Fecundity of Atractomorpha Sinensis (Orthoptera: Pyrgomorphidae)

Over the recent years, Atractomorpha sinensis I. Bolivar, has emerged as an important agricultural pest in China. However, the biological characteristics of A. sinensis remain largely unknown, which can hinder the prediction of its population dynamics. Thus, understanding the impact of temperature on the developmental period of A. sinensis is crucial to predict its population dynamics. The biological characteristics of A. sinensis were systematically observed at five different temperatures (16, 20, 24, 28, and 32°C) using the age-stage, two-sex life table method. The results demonstrated that the developmental period, preadult time, adult longevity, adult preoviposition period, and total preoviposition period were significantly reduced when the temperature was elevated from 16 to 32°C. The developmental threshold temperatures of egg, nymph, preoviposition period, female adult, male adult, and generation were 9.14, 10.44, 12.53, 10.97, 12.47, and 10.58°C, respectively, with the corresponding effective accumulated temperatures of 452.31, 575.99, 169.58, 528.13, 340.81, and 1447.95 degree-days. With an increase in temperature, the intrinsic rate of increase (r) and finite rate of increase (λ) were increased, while the mean generation time (T) was shortened. The optimal values of net reproductive rate (R0= 73.00 offspring) and fecundity (244.55 eggs) were determined at 24°C. Similarly, the population trend index (I) of A. sinensis was found to be highest at 24°C. Our findings indicate that A. sinensis has the greatest rate of population growth at 24°C, which can provide a scientific basis for predicting the in-field population dynamics of A. sinensis.

Demography of Cacopsylla chinensis (Hemiptera: Psyllidae) Reared on Four Cultivars of Pyrus bretschneideri (Rosales: Rosaceae) and P. communis Pears With Estimations of Confidence Intervals of Specific Life Table Statistics

The psyllid Cacopsylla chinensis (Yang & Li) (Hemiptera: Psyllidae) is a serious pest of pears in China. To determine and contrast the fitness of the psyllid on two endemic cultivars of Pyrus bretschneideri (i.e., BHXS and BSL) and two introduced cultivars of Pyrus communis (i.e., CB and CRB), we analyzed data on the development, survival, and fecundity from C. chinensis individuals reared on the four cultivars. The age-stage, two-sex life table theory was used in order to enable the inclusion of males in the analysis as well as a means of identifying the variation in developmental durations among individuals. Results indicated that C. chinensis can successfully develop and reproduce on all four pear cultivars. However, based on the lower preadult survival rate, longer preadult duration, longer total preoviposition period (TPOP), and lower fecundity that occurred on both cultivars of P. communis, these two cultivars are less favorable hosts for C. chinensis than the P. bretschneideri cultivars. The lower intrinsic rate of increase (r), finite rate of increase (λ), and net reproduction rate (R0) on CB and CRB pears showed these two introduced cultivars are more resistant to C. chinensis than the endemic BHXS and BSL pears. These resistant cultivars would be appropriate candidates for managing C. chinensis. We used the bootstrap technique to estimate the uncertainty of the population parameters (r, λ, R0, etc.), while also demonstrating that it can be used for estimating the 0.025 and 0.975 percentile confidence intervals of the age of survival rate.

RESPON BIOLOGIS BEBERAPA JENIS PARASITOID PADA LALAT PENGGOROK DAUN Liriomyza huidobrensis BLANCHARD

This research conducted to know the biological responses of leaf miner parasitoid Liriomyza huidobrensis is Hemyptarsenus varicomis Girault (Eulophidae), Opius sp (Braconidae) and Gronotoma micromorpha (Eucoilidae). Three species of parasitoid chosen as the substance of research caused by biological agent superiorities. On this research, there are some observed that is long life imagoes, preoviposition, oviposition period, after oviposition, The egg-laying rate, fertilization, daily fertilization, mortality and female proportion. This research was conducted for four-month at Ecology Laboratory and Insect Systematics and at the Green House of Pest and Plant Diseases Department, Faculty of Agriculture Udayana University in Denpasar. Used substance of host kidney bean (Vigna sinensis L ) host insect ( L. Huidobrensis ) and species of the parasitoid (H.varicornis, Opius sp and G.micromorpha) The experiments using randomized complete block design was used in this research. The observed results indicated that betwen three species of parasitoid used H.varicornis has preoviposition period and time after oviposition shortest so that to reproduce generation of H.varicornis faster than G.micromopha and Opius sp. At the meantime the fertilization level, and best female proportion produced of H.varicornis. Mortality on G.micromorpha and O.liriomyzae cause of paralyzing and host- feeding by H.varicornis. Mortality on G.micromorpha and Opius sp influential to female proportion number that produced that is the mortality of female generation caused of paralyzing and host-feeding by H. varicornis, So that fertilizing level, parasitisation level and female proportion higher happen if G.micromorpha or Opius sp released after releasing H. varicornis

Essential Oil Components in Superabsorbent Polymer Gel Modify Reproduction of Blattella germanica (Blattodea: Ectobiidae)

The use of essential oil components (EOCs) against the German cockroach, Blattella germanica (L.), has increasingly received attention from researchers. However, the determination of lethal doses/concentrations alone does not provide enough information on the range of biological effects of these EOCs. To improve our understanding of the potential effects of EOCs, we examined biological parameters of B. germanica exposed to sublethal EOCs formulated in gels. This study employed superabsorbent polymer (SAP) gel to prolong bioavailability of limonene, carvacrol, and β-thujaplicin, and evaluated how these EOCs shape biological parameters of B. germanica. Overall, median survival days ranged from 57 to 69.5 d for males and 73 to 99 d for females. The survival day ranking for the EOCs was limonene > β-thujaplicin > carvacrol. Carvacrol and β-thujaplicin gels reduced male longevity by at least 34 and 39%, respectively, while limonene had no effect. The longevity of females was reduced by limonene, but not by carvacrol and β-thujaplicin gels. EOCs significantly suppressed overall adult females’ reproductive period, oothecal hatchability, reduced fecundity, and interoothecal period, but not the number of oothecae formed and egg incubation period. The preoviposition period (mean: 2–25 d) ranking was limonene < carvacrol < β-thujaplicin. Based on these results, limonene, carvacrol, and β-thujaplicin in SAP gels show promising potential to reduce adult male survival/longevity, suppress egg hatchability and female fecundity, and delay the interoothecal period. These findings may represent the basis for the practical use of EOCs as a tactic in integrated pest management systems for B. germanica.

Effect of Constant and Fluctuating Temperature on the Development, Reproduction, Survival, and Sex Ratio of Phenacoccus solenopsis (Hemiptera: Pseudococcidae)

Effects of temperature on the development, survival, reproduction, longevity and sex ratio of the cotton mealybug, Phenacoccus solenopsis Tinsley, was assessed at five constant temperatures ranging from 20 to 35°C and five fluctuating temperatures ranging from 15 to 40°C under laboratory conditions. Results showed that nymphal development duration, preoviposition period, oviposition period, fecundity, and adult longevity were reduced significantly with increasing temperature until 30°C, but developmental duration of third female nymphal instar and female adult longevity was longer at 35°C than 30°C, and no males could emerge from pupae at the constant temperature 35°C. Fluctuating temperature, in general, significantly accelerated the nymphal developmental duration, prolonged preoviposition period, shortened oviposition period, reduced fecundity, lowered the survival rate of nymphs, and decreased adult longevity of males and females compared to their mean corresponding constant temperature. Overall, it is suggested that one should be prudent when applying the obtained results under constant and fluctuating temperatures under laboratory conditions.