Optimizing Laboratory Rearing of a Key Pollinator, Bombus impatiens

Bumble bees are key pollinators for wild and managed plants and serve as a model system in various research fields, largely due to their commercial availability. Despite their extensive use, laboratory rearing of bumble bees is often challenging, particularly during the solitary phase queens undergo before founding a colony. Using a literature survey, we demonstrate that most studies rely on commercially available species that are provided during the colony’s social phase, limiting study on early phases of the life cycle and the ability to control for colony age and relatedness. Laboratory rearing is challenging since the queen solitary phase is less understood compared to the social phase. To overcome this barrier, we examined several aspects related to the queen solitary phase: the effect of age on likelihood of mating, how the timing of CO2 narcosis post-mating (a technique to bypass diapause) affects egg-laying, and whether different social cues affect the success of colony initiation. Our data show an optimum age for mating in both sexuals and decreased egg-laying latency in the presence of workers and pupae. The timing of CO2 narcosis did not significantly affect egg laying in queens. These findings can be incorporated to improve bumble bee rearing for research purposes.

Design and testing of stability improvement of nine multi-level H-Inverter for distribution system

<p class="Abstract">In this article, a solitary phase nine-level series connected H-Bridge powered by photovoltaic MPPT based SHAPF in view of basic controller is proposed. SRF is utilized for reference input current extraction and to create pulses for the SHAPF. The principle point of the cascaded bridge is to dispense harmonics, enhance power factor and reactive energy compensation of the single-phase distribution framework. The suggested control calculation has two parts, changing the load current into stationary reference outline directions and estimation of peak amplitude of load currents. Consequently, a basic and dependable controller effortlessly of execution was created. The calculation for single-phase SHAF is intending to perform with exact tracking performance under step changes in load currents and to give great dynamic compensation. In this article, synchronous reference theory PLL with Inverse-Park change is adopted for producing quadrature part of current. The execution of the control calculation is tried and assessed utilizing MATLAB/Simulink tool.</p>

Ls-II: An Improved Locust Search Algorithm for Solving Optimization Problems

The Locust Search (LS) algorithm is a swarm-based optimization method inspired in the natural behavior of the desert locust. LS considers the inclusion of two distinctive nature-inspired search mechanism, namely, their solitary phase and social phase operators. These interesting search schemes allow LS to overcome some of the difficulties that commonly affect other similar methods, such as premature convergence and the lack of diversity on solutions. Recently, computer vision experiments in insect tracking methods have conducted to the development of more accurate locust motion models than those produced by simple behavior observations. The most distinctive characteristic of such new models is the use of probabilities to emulate the locust decision process. In this paper, a modification to the original LS algorithm, referred to as LS-II, is proposed to better handle global optimization problems. In LS-II, the locust motion model of the original algorithm is modified incorporating the main characteristics of the new biological formulations. As a result, LS-II improves its original capacities of exploration and exploitation of the search space. In order to test its performance, the proposed LS-II method is compared against several the state-of-the-art evolutionary methods considering a set of benchmark functions and engineering problems. Experimental results demonstrate the superior performance of the proposed approach in terms of solution quality and robustness.

BEHAVIORAL ADAPTATIONS OF AN AFRICAN PONERINE ANT IN THE CAPTURE OF MILLIPEDES

Workers of the ponerine ant Plectroctena minor are equipped with hypertrophied mandibles that can seize tubular millipedes, their essential prey, of up to 4 mm in diameter. We studied their predatory behavior in four situations where they captured spirostreptid millipedes. (1) P. minor workers generally seized millipedes of less than 4 mm in diameter dorsally and by their anterior part. During seizure the mandibles slipped on the exoskeletal coils of the millipede body and were caught between two segments that were slightly separated by the strong pressure. This facilitated stinging that mostly occurred ventrally in the soft intersegmentary space of the seized zone. (2) When a millipede was more than 4 mm in diameter, the workers seized it by an appendage before stinging or by wrapping themselves around the prey, then recruited nestmates in order to retrieve it. (3) The workers probably perceived kairomones from millipedes rolled into sloughing lodges as they opened the lodges and singly captured individuals less than 4 mm in diameter. Larger individuals (more than 4 mm in diameter) were captured after the workers recruited nestmates that generally cut up these prey on the spot. (4) When encountered in a test-tube simulating galleries, 95 to 105 mmlong millipedes (around 8 mm in diameter) were always captured. When the millipede's head was near the test-tube opening, the workers gripped the antennae or mandibles and stung the extreme anterior part of the millipede body, triggering rapid paralysis. In this case, they were even able to singly master then to retrieve these millipedes 94 to 117 times their weight, which represents the highest ratio for a solitary hunting strategy in ants. When the hind part of the millipede was near the test-tube opening, seizure was difficult and nestmates were recruited in most cases. We concluded that the behavioral flexibility of P.minor, which mainly occurred during the solitary phase of prey mastering, permitted the capture of millipedes of a wide range of sizes.

TAXONOMIC STATUS OF THE ROCKY MOUNTAIN LOCUST: MORPHOMETRIC COMPARISONS OF MELANOPLUS SPRETUS (WALSH) WITH SOLITARY AND MIGRATORY MELANOPLUS SANGUINIPES (F.)

Morphometric analysis of 16 body measurements of migratory and solitary Melanoplus sanguinipes (F.) and M. spretus (Walsh) was used to determine if M. spretus was, in fact, the migratory phase of M. sanguinipes. Migratory M. sanguinipes was found to be more similar to its own solitary phase than to M. spretus. Melanoplus spretus resembled migratory M. sanguinipes, but in 14 comparisons M. spretus differed significantly from both solitary and migratory M. sanguinipes. Despite the potential for environmental variation obscuring differences in morphology, the divergent morphometric characters of M. spretus and the phases of M. sanguinipes appear to justify the status of M. spretus as a true species.

Evidence of persistent populations of the African armyworm, Spodoptera exempta (walker) (lepidoptera: noctuidae), in east-central Tanzania

There is a growing body of evidence to suggest that low density populations of Spodoptera exempta (Walker) in the solitary-phase can persist during the dry season in certain localities in eastern Africa. Moths were caught in simple pheromone traps for several months after the estimated dates of emergence of larval outbreaks in central Tanzania in 1980 and from 1982 to 1984. This provided evidence for the occurrence of a shifting population between the Uluguru Mountains and the swampy coastal areas, in east-central Tanzania, for a large part of the year. Central Tanzania is an important area for the development of the first outbreaks of the season in eastern Africa and for any control strategy. It has been suggested that S. exempta fits the criteria for an r-selected species. However, the low migratory capacity of low-density populations indicates rather that the species spreads out its risks in space and time. A theoretical genetic mechanism controlling the distance flown by moths may enable the species to exhibit both migratory and non-migratory strategies. Thus both ephemeral and continously favourable habitats may be exploited.