Reproductive Potential Accelerates Preimaginal Development of Rebel Workers in Apis mellifera

Rebel workers develop from eggs laid by the previous queen, before it went swarming and left the colony orphaned, until the emergence of a new queen. In contrast to normal workers developing in the queen’s presence, rebels are set to reproduce and avoid rearing of successive bee generations. They have more ovarioles in their ovaries, as well as more developed mandibular glands and underdeveloped hypopharyngeal glands, just like the queen. We posited that rebels are not only similar to queens in some anatomical features, but also develop in a shorter time in comparison to normal workers. Therefore, the aim of this study was to compare preimaginal development duration in rebel and normal workers. The results show that rebels, i.e., workers with a higher reproductive potential, had a significantly shorter preimaginal development period (mean ± SD, 19.24 ± 0.07 days) than normal workers (22.29 ± 0.32 days). Our result confirmed that workers who develop in a queen-less colony undergo a shorter preimaginal development than those in a queen-right colony.

Food as a factor of fertility, development duration, and changes in morphometric parameters in Henosepilachna vigintioctomaculata (Motschulsky)

Relevance.The physiology of insects nutrition and digestion reflects the diversity of their food specialization, aimed at the most effective use of feed. The choice of the object of nutrition is provided by attractants in it, as well as the presence of substances necessary for the insect to pass the stages of development and general nutrition. On the other hand, the “plant-phytophage” system has well-developed barriers that limit the choice of plants by insects for settling, feeding, and eggs laying. In the modern literature, there is very little information on the effect of food plants on fertility, development duration, and changes in morphometric parameters in 28-spotted potato ladybird Henosepilachna vigintioctomaculata (Motschulsky). However, they are important for understanding the ecology of the pest and developing effective control measures.Research methodology. The laboratory colony of Henosepilachna vigintioctomaculata (Motschulsky) was established in 2019. Adults were collected in various locations throughout Primorsky Territory, Russia. For an introduction into the culture of the insectarium, imagos, clutches, and larvae were collected in natural habitats. Standard methods of keeping and breeding insect cultures were used, aimed at optimizing the parameters of the environment, the density of the content, and the feed supply.Results. The uneven influence of crops on different aspects of the ontogenesis of the potato ladybird was revealed. The potato was the most favorable food in most experiments. When feeding with this crop, the smallest incubation period of eggs, the largest sizes of larvae of initial ages, the largest sizes of pupae, fertility, low mortality was observed, and as a result, the largest growth coefficient (3.22±0.22) and the shortest period of development from eggs to imago (21.3±0.81) were revealed. The remaining forage plants used in the study showed a less unambiguous result. The different influence of crops on both individual indicators and the ontogenetic periods of the phytophage was found. When eating tomato, cucumber, pumpkin, lime, high overall mortality was noted. At the same time, linden stimulated the development of eggs and the growth of young larvae but provoked low fertility and a general prolongation of the development period. According to the set of characteristics, pumpkin, cucumber, and linden were the least favorable for nutrition.

Effect of different nutrient diets on developmental and reproductive fitness of Pink bollworm, Pectinophora gossypiella (Lepidoptera: Gelechiidae)

Pink bollworm, Pectinophora gossypiella (Lepidopetra: Gelechiidae) is one of the most important pest of cotton. In this paper, we studied the influence of different nutrient rearing diets on developmental and reproductive characteristics of pink bollworm under laboratory conditions. Larvae were reared on four diets (two natural diets and two artificial diets) with varied nutritional value. Larval diet affects the survival, development duration, pupal weight, adult emergence and fecundity. Pink bollworm attained the fastest larval development on NRD (19.8 days) with a survival rate of 88.2% and slowest on NPD and okra (~ 27.1 days) with a survival rate of 47.5% and 58.1% respectively. Pupal weight was highest (26.86 mg) on NRD and reached maximum fecundity (107 eggs/female), while lowest fecundity on NPD (37 eggs/female). Among natural diets, egg hatching rate on cotton and okra were 87% and 71%. Adult emergence starts early and the adult eclosion window was narrow on cotton and NRD. Adult longevity was varied with diets, while female moths lived longer than males in all diet treatments. Our study may help to understanding the effect of nutrition from different diets and enhanced the fecundity of P. gossypiella on NRD under laboratory conditions.

Fusarium Head Blight Infestation in Relation to Winter Wheat End-Use Quality—A Three-Year Study

Fusarium head blight (FHB) is one of the major threats for wheat production worldwide. It reduces yield, quality, and feeding value of wheat grains. In addition, mycotoxins produced by Fusarium pathogens can have a negative effect on livestock and human health. The aim of this study was to assess changes in technological quality traits and end-use quality of winter wheat varieties after artificial inoculation with Fusarium spp. over three years. Differences in dough development duration and extensibility were measured as the means of relative reductions due to different environments and varieties’ characteristics. Differences in dough softening during kneading were determined as the means of relative increases due to FHB inoculation. In addition, dough had reduced strength, was stickier, and therefore was more difficult to handle, due to a decrease of the average energy value and resistance to extension in FHB-inoculated wheat, compared to naturally infected plants. Dough development time, stability, and resistance usually varied is a similar way, with FHB-resistant varieties showing a good response to FHB inoculation and maintaining good quality. Increasing the level of Fusarium spp. contamination in more FHB-susceptible wheat varieties worsened their technological quality, primarily, the sedimentation value and the gluten index, and hence had a negative effect on the rheological properties.

Effect of Different Plants on the Growth and Reproduction of Thrips flavus (Thysanoptera: Thripidae)

Host plants play an important role in affecting insect development and reproduction. Understanding the host plant preferences is important for pest control. Thrips flavus Schrank (Thysanoptera: Thripidae) is a worldwide phytophagous pest in Palearctic Asian and European countries. We used a life table analysis to study the development duration, population parameters, and population growth of T. flavus on five plant species, including Solanum melongena (Solanaceae), Capsicum annuum (Solanaceae), Glycine max (Leguminosae), Brassica rapa var. glabra (Cruciferae), and Cucumis sativus (Cucurbitaceae). The results showed that T. flavus can survive and reproduce on Cu. sativus and G. max, which were two potentially suitable host plants. T. flavus preferred to oviposit on Cu. sativus with a shorter duration of development (17.8 days) at 25 °C. Therefore, the host plant was an important factor influencing the development and fecundity of T. flavus populations. These results will improve our understanding of the population dynamics of T. flavus and facilitate the development of more scientific and efficient measures to control thrips.

Influence of temperature on the development and reproduction of Cinara cedri (Hemiptera: Aphidoidea: Lachninae)

Temperature is one of the main factors affecting insect growth, development and reproduction. The effects of temperatures (10, 15, 20, 25 and 30°C) on the development and reproduction of Cinara cedri Mimeur (Hemiptera: Aphidoidea: Lachnidae) fed on Cedrus deodara (Roxb.) G. Don were evaluated in this study. With the increase of temperature from 10 to 30°C, the development duration at different development stages gradually shortened. There was a significant positive correlation between the developmental rates and temperature, following a quadratic regression model. The lower developmental threshold temperature (C) and effective accumulated temperatures (K) for completing a generation were 4.13°C and 263.4 degree-days, respectively. The highest fecundity was observed at 20°C with 25.74 first-instar nymphs/female. Both the highest intrinsic rate of increase (r, 0.11 ± 0.03) and net reproduction rate (R0, 19.06 ± 2.05) were observed at 20°C, whereas the lowest values of r (0.05 ± 0.01) at 10°C and R0 (5.78 ± 0.88) at 30°C were observed. The results suggest that temperature significantly affects the biology of C. cedri and the optimal temperature for its development is 20°C.

Clutch quality is related to embryonic development duration, hatchling body size and telomere length in the spined toad (Bufo spinosus)

Reproductive success is often related to parental quality, a parameter expressed through various traits, such as site selection, mate selection and energetic investment in the eggs or progeny. Owing to the complex interactions between environmental and parental characteristics occurring at various stages of the reproductive event, it is often complicated to tease apart the relative contributions of these different factors to reproductive success. Study systems where these complex interactions are simplified (e.g. absence of parental care) can help us to understand how metrics of parental quality (e.g. gamete and egg quality) influence reproductive success. Using such a study system in a common garden experiment, we investigated the relationships between clutch hatching success (a proxy of clutch quality) and offspring quality in an amphibian species lacking post-oviposition parental care. We found a relationship between clutch quality and embryonic development duration and hatchling phenotype. We found that hatchling telomere length was linked to hatching success. These results suggest that clutch quality is linked to early life traits in larval amphibians and that deciphering the influence of parental traits on the patterns we detected is a promising avenue of research.

Morphological characteristics of Indonesian Rubus flowers

Normasiwi S, Salamah A, Surya MI. 2021. Morphological characteristics of Indonesian Rubus flowers. Biodiversitas 22: 1441-1447. Rubus spp. are woody or herbaceous plants that can be used for fruit, ornamental and medicinal purposes. The increasing use of Rubus as a commercial species is highly dependent on the formation of high-quality genetic material. However, the lack of basic biological knowledge is one of the limiting factors in this development. This research aims to describe the morphological characters of Indonesian Rubus flowers at Cibodas Botanical Garden, Indonesian Institute of Sciences, Cianjur, West Java, Indonesia. From January to June 2020, we observed nine Rubus species with five replications, namely R. alceifolius, R. chrysophyllus, R. ellipticus, R. fraxinifolius, R. linneatus, R. moluccanus, R. pyrifolius, R. rosifolius, and Rubus sp (Blackberry) in Cibodas Botanical Garden, Indonesia. The results showed variations in the characteristics of the pistil, stamens, torus shape, and duration of flowering stages between species. The mean value of the stamen-pistil ratio for R. pyrifolius was highest among other species (8.27), and R. fraxinifolius was the lowest (0.16). Furthermore, a correlation analysis between stamens and pistils for nine Rubus species was relatively positive (r = 0.598), similarly distinctly positive between pistils and fruits with r = 0.763. Flower development duration takes ranging 10-12 days from initiation to anthesis, depending on the species.

An automation-based adaptive seamless design for dose selection and confirmation with improved power and efficiency

In a drug development program, the efficacy and safety of multiple doses can be evaluated in patients through a phase 2b dose ranging study. With a demonstrated dose response in the trial, promising doses are identified. Their effectiveness then is further investigated and confirmed in phase 3 studies. Although this two-step approach serves the purpose of the program, in general, it is inefficient because of its prolonged development duration and the exclusion of the phase 2b data in the final efficacy evaluation and confirmation which are only based on phase 3 data. To address the issue, we propose a new adaptive design, which seamlessly integrates the dose finding and confirmation steps under one pivotal study. Unlike existing adaptive seamless phase 2b/3 designs, the proposed design combines the response adaptive randomization, sample size modification, and multiple testing techniques to achieve better efficiency. The design can be easily implemented through an automated randomization process. At the end, a number of targeted doses are selected and their effectiveness is confirmed with guaranteed control of family-wise error rate.

Autophagy: a necessary defense against extreme cadmium intoxication in a multigenerational 2D experiment

Autophagy is a natural process that aims to eliminate malfunctioning cell parts, organelles or molecules under physiological conditions. It is also induced in response to infection, starvation or oxidative stress to provide energy in case of an energy deficit. The aim of this 2-dimensional study was to test if, and if so, how, this process depends on the concentration of cadmium in food (with Cd concentrations from 0 to 352 μg of Cd per g of food (dry weight)—D1 dimension) and the history of selection pressure (160 vs 20 generations of exposure to Cd—D2 dimension). For the study, the 5th instar larvae of a unique strain of the moth Spodoptera exigua that was selected for cadmium tolerance for 160 generations (44 μg of Cd per g of food (dry weight)), as well as 20-generation (11, 22 and 44 μg of Cd per g of food (dry weight)) and control strains, were used. Autophagy intensity was measured by means of flow cytometry and compared with life history parameters: survivability and duration of the 3rd larval stage. The highest values of autophagy markers were found in the groups exposed to the highest Cd concentration and corresponded (with a significant correlation coefficient) to an increased development duration or decreased survivorship in the respective groups. In conclusion, autophagy is probably initiated only if any other defense mechanisms, e.g., antioxidative mechanisms, are not efficient. Moreover, in individuals from pre-exposed populations, the intensity of autophagy is lower.