Understanding why animals choose one food over another is one of the key questions underlying the fields of behaviour ecology. This study aims to test if ladybird beetle, Propylea dissecta Mulsant (Coleoptera: Coccinellidae) can forage selectively for nutrients in order to redress specific nutritional imbalances to maximise their fitness. We hypothesised that the presence of more food choices leads to bad decisions in terms of their food selection which ultimately negatively affects the mating and reproductive parameters of P. dissecta. To test this, we first manipulated the predator's nutritional status by rearing them in five separate dietary groups from first instar larvae to newly emerged adult stage. Thereafter, we tested their food choice between five different foods, i.e. Aphis craccivora Koch, Aphis nerii Boyer de Fonsclombe, conspecific eggs, heterospecific eggs and mixed pollen grains, equidistantly placed in a Petri dish. Based on the food choice of the newly emerged adults, they were reared on the chosen diet for 10 days. Thereafter, adults were paired with their opposite sex (collected from stock culture reared on A. craccivora) and mating and reproductive parameters were recorded. Our results suggested that the variety of food did not affect the food choice of ladybird beetle, P. dissecta. They tend to choose their natural diet, i.e. aphid in each dietary regime. We found that previous dietary regime, i.e. larval dietary regime, significantly influences the mating and reproductive parameters of both the male and female except for the time to commence mating by the male. Food choices of adult beetles were found to significantly influence the time to commence mating, average fecundity and per cent egg viability in males and only mating duration in females. Our findings suggest that P. dissecta consistently made optimal decisions when facing various food choices. They consistently preferred their natural and preferred food choice over others, indicating a strong food selection behaviour.

The sustainability of grazed rangelands can be improved by adopting innovative management practices that enhance the ecological resilience, productivity, and long-term viability of rangeland ecosystems. This study applied a bivariate Multiple Indicator–Multiple Causation model to examine how landowner characteristics are associated with their perceptions concerning patch-burn grazing (PBG) and mixed-species grazing (MSG). Data were collected through a mail survey of landowners in the Southern Great Plains who own at least 100 acres. The significant and positive correlation between PBG and MSG suggests that their relative preference tends to change together, potentially allowing them to complement when implemented together.

Low Stokes number particles at dilute concentrations in turbulent flows can reasonably be approximated as passive scalars. The added presence of a drift velocity due to buoyancy or gravity when considering the transport of such passive scalars can reduce the turbulent dispersion of the scalar via a diminution of the eddy diffusivity. In this work, we propose a model to describe this decay and use a recently developed technique to accurately and efficiently measure the eddy diffusivity using Eulerian fields and quantities. We then show a correspondence between this method and standard Lagrangian definitions of diffusivity and collect data across a range of drift velocities and Reynolds numbers. The proposed model agrees with data from these direct numerical simulations, offers some improvement to previous models in describing other computational and experimental data and satisfies theoretical constraints that are independent of Reynolds number.

Parthenium hysterophorus Linnaeus (Asteraceae), commonly known as “congress grass,” is among the 10 worst weeds of India and is considered one of the world’s 100 most harmful invasive species. This species has been introduced accidentally into several countries, including India, and is a major agricultural and rangeland weed in more than 45 countries. It affects crop production, suppressing biodiversity, crop yields, the health of farm animals and human beings, and local and regional economies. Biological control has been found to be a cost-effective management strategy to control the weed, with the leaf beetle, Zygogramma bicolorata Pallister (Coleoptera: Chrysomelidae), considered an effective and safe biocontrol agent. Several studies have investigated the beetle’s biology, reproduction, and other life attributes. This review compiles the existing information about Z. bicolorata biology, growth, development, reproduction, food, and host specificity, and the effects of abiotic and biotic stressors on the insect’s life attributes. We anticipate that this review will helpful for improving strategies for this bioagent’s swift mass rearing and for developing classical biological control design for Parthenium weed.

Programmes focused on buffer zones (BZs) and park revenue-sharing (PRS) are aimed at sharing protected area (PA) benefits with local communities to meet their development needs and, in turn, improve the PA–people relationship. However, whether and how these programmes improve public attitudes towards PAs is little understood. We assessed how residents perceive the benefit and burdens of Nepal’s BZ programme, which shares up to 50% of PA revenue with communities, and how this process relates to their perceptions of change in the PA–people relationship since the BZ programme was implemented. Survey results from 2122 households in the BZs of six PAs showed that residents’ perceptions of PA–people relationships had improved since the BZ programme’s implementation. Furthermore, the perceived trend in the PA–people relationship was positively related to the perception of benefits and satisfaction with coordination between the PA and local government; it was negatively related to perceived burdens of BZ-related laws in rural development, history of damage/loss from wildlife and misunderstandings of the purpose behind BZ funds being given to local communities. These findings provide valuable insights for PA managers in Nepal and worldwide in designing new or improving existing mechanisms of benefit-sharing with local people and to improve PA–people relationships.

Food preferences and choices are common among animals, including insects. Studies on food preferences have been done on coccinellids using eggs and aphids as diet, but information on the food choices of the aphidophagous ladybird, Propylea dissecta (Coleoptera: Coccinellidae), under laboratory conditions, is scarce. This study examined the effect of physical activity (walking) on food choice. We reared P. dissecta larvae on aphids, Aphis craccivora (Hemiptera: Aphididae), until the fourth-instar stage, and then allowed the fourth-instar larvae to walk on a glass rod for different time intervals to illustrate the energetic costs of foraging. After walking, larvae were provided simultaneous food choices of equidistantly placed food, i.e., A. craccivora, conspecific eggs, and heterospecific eggs. As the walking time duration gradually increased, the level of larval activity increased, resulting in poorer food choices.

Intraspecific variation is the variation in morphology, physiology, behaviour, and social organisation of any species as it adapts to changing environmental circumstances by varying its feeding habits. In the present study, we investigated the disparities between the preselected (F1) and postselected (F15) populations of Propylea dissecta Mulsant (Coleoptera: Coccinellidae) when fed on four different prey species, namely Aphis gossypii Glover from bottle gourd, Lagenaria vulgaris Seringe (Cucurbitaceae), Lipaphis erysimi (Kaltenbach) from mustard, Brassica campestris Linnaeus (Brassicaceae), Rhopalosiphum maidis (Fitch) from maize, Zea mays Linnaeus (Poaceae), and Uroleucon compositae (Theobald) from chrysanthemum, Chrysanthemum indicum Linnaeus (Asteraceae), under an experimental evolution study. A simple bimodal pattern of distribution was obtained for each prey species, which was warped with variations in prey species for both F1 and F15. This research might provide the basis for further studies on the differential pace of development of various other prey species, improve understanding of ecological evolution, and provide a spectrum of fast-growing bioagents for the introduction of biological control strategy in pest management techniques against agropests.

The effects of selection on developmental variants have not yet been rigorously investigated on variable prey quantities. We investigated the food exploitation strategy of first (F1) and fifteenth (F15) generation slow and fast developers of Propylea dissecta (Mulsant) in the presence of scarce and abundant quantities of pea aphid, Acyrthosiphon pisum (Harris), and its effect on adult body mass and reproductive attributes. Both selected slow developers and selected fast developers were higher in number than their counter unselected generation on scarce and abundant diets, respectively. Immature survivals of selected slow developers were depressed after the selection process while it was enhanced for selected fast developers on both diet regimes. On both diets, the total developmental duration was longer for selected slow developers and shorter for selected fast developers. Fecundity and percent egg viability were greater in selected fast developers with plentiful prey supply and lower in control slow developers with inadequate prey supply. More adult body mass was found for pre-selected slow developers than selected slow developers on a scarce diet but selected fast developers enhanced their body weight than unselected individuals of fast developers on an abundant diet. The present experimental evolution findings point to the presence and persistence of developmental variations with variability in their developmental and reproductive traits on allocating scarce and abundant prey supplies.

In the present study, we assessed functional response curves of two generalist coccinellid beetles (Coleoptera: Coccinellidae), specifically Menochilus sexmaculatus and Propylea dissecta, using fluctuating densities of aphid prey as a stimulus. In what may be the first such study, we investigated how the prey density experienced during the early larval development of these two predatory beetle species shaped the functional response curves of the late instar–larval and adult stages. The predators were switched from their rearing prey-density environments of scarce, optimal, or abundant prey to five testing density environments of extremely scarce, scarce, suboptimal, optimal, or abundant prey. The individuals of M. sexmaculatus that were reared on either scarce- and optimal- or abundant-prey densities exhibited type II functional response curves as both larvae and adults. However, individuals of P. dissecta that were reared on scarce- and abundant-prey densities displayed modified type II functional response curves as larvae and type II functional response curves as adults. In contrast, individuals of P. dissecta reared on the optimal-prey density displayed type II functional response curves as larvae and modified type II functional response curves as adults. The fourth-instar larvae and adult females of M. sexmaculatus and P. dissecta also exhibited highest prey consumption (T/Th) and shortest prey-handling time (Th) on the scarce-prey rearing density. Thus, under fluctuating-prey conditions, M. sexmaculatus is a better biological control agent of aphids than P. dissecta is.

Food availability is a fundamental factor determining an animal's potential fitness. Carry-over effects of food limitation from development to adulthood are known to influence reproduction, ageing, and tolerance to stress. We have examined the effect of stage-specific variation (before adult emergence or pre-emergence, post-emergence and post-mating) in food availability in Propylea dissecta (Mulsant). Larvae were reared separately on two different pre-emergence food regimes (abundant or restricted) until pupation. Newly emerged adults were further split into two groups and placed on abundant or restricted post-emergence regimes. After mating, females were split and reared on any one of two post-mating regimes. The results revealed that: (i) time to commence mating declined with increased food availability in pre- and post-emergence stages, (ii) mating duration increased with food availability post-emergence, (iii) highest reproduction output was observed in individuals who had abundant food pre- and post-emergence. However, food availability at the time of oviposition also had a strong influence on fecundity. Solo bouts of scarcity, regardless of which stage suffered them, were effectively managed in at least two of the three stages (pre-emergence, post-emergence, post-mating) had abundant food.

Operational sex ratio and paternal age are known to independently affect mating behaviour and reproductive performance. We conducted experiments to assess the effects of operational sex ratio and paternal age on mating, reproduction, and total development duration of Menochilus sexmaculatus (Fabricius) (Coleoptera: Coccinellidae). Three male-biased sex ratios, no (1:1), modest (1:2), and extreme (1:5) competition treatments, were formed using young, middle-aged, and old males. The reproductive performance of M. sexmaculatus at all ages under extreme competition (1:5) surpassed the other two treatments. More competition among males decreased the time of commencement of mating and increased the duration of copulation. Females laid a greater number of eggs in extreme competition treatments. The operational sex ratio (irrespective of age) had no significant effect on the total developmental duration of offspring. Among different age groups, older males took more time to commence mating and mated for longer durations in all the sex ratio treatments. The number of eggs in the first clutch was lowest when females were mated with older males with increased offspring development duration. Thus, it can be concluded that male-biased sex ratio elevates the performance of M. sexmaculatus. Among different age groups, older males were poor performers than young and middle-aged males.

We have discovered a population of 29 outlying Hα emitters which appear like unresolved blobs in the DR14 data release of the SDSS IV MaNGA integral field unit survey. They do not have any underlying optical continuum emission in deep imaging from the DECam Legacy Survey or Beijing-Arizona Sky Survey. These blobs either lie away from the disc of the host galaxy in the MaNGA IFU and/or have velocities which are different from the velocity map of the host galaxy. Interestingly, all of them show photoionisation due to star formation. These galaxies have very high specific star formation rates compared to the known population of dwarf galaxies. However, their metallicities are consistent with or even lowerthan those of the local volume dwarfs. Thus, we can possibly rule out tidal dwarf galaxies. They could represent a new population of low mass and starbursting dwarf galaxies.

A recent study on ladybird, Menochilus sexmaculatus (Fabricius) demonstrates that males perform post-copulatory mate guarding in the form of prolonged mating durations. We investigated whether food resource fluctuation affects pre- and post-copulatory behaviour of M. sexmaculatus. It has not been studied before in ladybirds. For this, adults were subjected to prey resource fluctuations sequentially at three levels: post-emergence (Poe; 10 days), pre-mating (Prm; 24 h) and post-mating (Pom; 5 days; only female). The food resource conditions at each level could be any one of scarce, optimal or abundant. Pre-copulatory and post-copulatory behaviour, and reproductive output were assessed. Post-emergence and pre-mating nutrient conditions significantly influenced the pre-copulatory behaviour. Males reared on scarce post-emergence conditions were found to require significantly higher number of mating attempts to establish mating unlike males in the other two food conditions. Under scarce post-emergence and pre-mating conditions, time to commencement of mating and latent period were high but opposite result was obtained for mate-guarding duration. Fecundity and per cent egg viability were more influenced by post-mating conditions, with scarce conditions stopping oviposition regardless of pre-mating and post-emergence conditions. Present results indicate that pre- and post-copulatory behaviour of ladybird is plastic in nature in response to food resource fluctuations.