Oviposition Events Research Articles

Pollination ecology of Dracula erythrochaete (Orchidaceae): brood-site imitation or food deception?

Abstract Pleurothallidinae is the most diverse Neotropical subtribe in Orchidaceae and is almost exclusively pollinated by insects of the order Diptera. Dracula, a genus of 138 species in the Pleurothallidinae, is known to attract Zygothrica (Drosophilidae) flies, common macrofungi visitors, by imitating fungal volatile compounds and lamellae. Interestingly, Dracula orchids do not appear to offer any rewards to their floral visitors. While brood-site imitation of macrofungi has been suggested as their pollination system, the exact behaviour of flies during their extended visits to the orchid flowers has yet to be confirmed. In this study, we document the pollination mechanism of Dracula erythrochaete. We characterize the floral structures involved in the mechanism using anatomical and morphological evidence. Additionally, through in situ observations and camera recordings, we describe the insect behaviour. We show that flowers of D. erythrochaete share the same group of visitors as nearby macrofungi, including different Zygothrica species, seven of which were determined as effective pollinators. Male and female flies were attracted to the flowers and displayed feeding behaviour. Accordingly, proteins were detected in high concentrations on the papillae at the base of the movable lip and in papillary trichomes of the sepals, near the column. The concept of brood-site imitation is debated, as no oviposition events were observed and no eggs were found on the flowers. Therefore, a mixed strategy of congregation/brood-site imitation and food reward is proposed for pollination.

The influence of resource patch condition and size on social interactions, reproductive behaviors, and oviposition in a fungivorous beetle

Variation among resource patches can structure spatial patterns of social behavior. Individual preferences and requirements for heterogeneous resources can lead to differences in where behaviors take place and which kinds of individuals interact. In this study we examined whether properties of habitat patches predict presence of and interactions among wild forked fungus beetles (Bolitotherus cornutus). B. cornutus use shelf-like fruiting bodies of wood decaying fungi (brackets) as social arenas, courtship and mating sites, oviposition locations, and food sources. Brackets on a single log vary in size and condition and represent a dynamic resource as individual brackets decay over the years that they persist on a subpopulation. We found that size and condition significantly predicted how a bracket was used by B. cornutus. Both males and females were found more often on larger, living brackets. Larger brackets hosted proportionally more social interactions and mating behaviors relative to the overall visitation by individuals. The relationship between these resource properties and frequencies of behaviors was stronger for reproductive, between-sex social interactions. Live brackets also attracted more oviposition events by females, but bracket size had no effect on this behavior. Our results indicate that the dynamics of growth and aging of a critical resource can impact how social and reproductive behaviors are distributed in time and space, which in turn could affect the social structure of subpopulations.Significance statementSpecies that depend on critical host resources are often faced with a patchy landscape of resource quality. Those patches represent the infrastructure within which social behaviors take place, and can have formative effects on where, when, and how social interactions occur. We demonstrated that the size and condition of a fungal resource predicted male and female forked fungus beetle presence and behavior. Larger, living brackets hosted more beetles overall, while larger brackets in any condition hosted more social interactions and mating behaviors. Female beetles were more likely to lay eggs on living brackets, regardless of size. This study demonstrates how ecological dynamics of aging resource patches can indirectly structure social landscapes by influencing where and how individuals interact.

Impact of age on the reproductive output of Hermetia illucens (Diptera: Stratiomyidae).

The current study examined the impact of adult black soldier fly (Hermetia illucens (L.)), age on reproductive output. Four treatments consisting of an equal sex ratio of the following combinations were used: 2-day-old males with 2-day-old females (YMYF); 6-day-old males with 2-day-old females (OMYF); 2-day-old males with 6-day-old females (YMOF); 6-day-old males with 6-day-old females (OMOF). Adult age was a significant factor for the overall number of mating events observed, with YMYF having 2.2× more than YMOF and 2.7× more than OMOF. Time was a significant factor in the number of mating events observed, with 97.8% observed on days 2-6. Age was not a significant factor for the total number of oviposition events, but the inclusion of time as a factor was significant, with 91.5% of all events occurring on days 2-6. Treatment and trial significantly interacted with egg production. This response can be attributed to treatments containing old females, which had a 50% variation in egg output across trials. Treatments containing young females were consistent in terms of egg production. As anticipated, due to oviposition events, 94.8% of total eggs were oviposited on days 2-6. Fecundity and egg hatch were also significantly impacted by female age, with a 50% reduction in both cases across trials occurring in old females. Young females paired with old males had a 20% reduction in egg hatch, but this difference was not statistically significant.

Initial blow fly (Diptera: Calliphoridae) colonization of cats (Felis catus) in Indiana.

Many disciplines are utilized within the field of veterinary forensic sciences, including forensic entomology. Understanding the initial colonization period by flies of forensic importance can contribute to estimating the minimum postmortem interval. There is limited data regarding the time of colonization of animals with fur, and the interpretation of this data is difficult due to the variation in animal models used. The purpose of this study was to examine the initial insect colonization of cats (Felis catus), with light and dark fur. Twelve domestic short-haired cats were placed in cages 15.2 m apart in a grassy field in West Lafayette, IN, United States. Weather data (temperature, precipitation, sun/cloud exposure, humidity), insect activity, time to oviposition, and decomposition changes were documented. Eggs from initial oviposition events were collected and reared to identify the primary colonizing species. Although the time of first oviposition event was not different between the treatments, fur color did affect fly colonization, and cats with dark fur had more oviposition events than cats with light fur (t = 2.639, df = 4, P = 0.029). Three species of Lucilia (Diptera: Calliphoridae) colonized the cats on the initial day of placement. Further studies in cats should include the decompositional studies to understand the unique characteristics that occur during each stage of decomposition, which could aid in developing a scoring system for animals with fur. Additional studies could include analyzing how fur length would affect colonization.

Lucilia silvarum Meigen (Diptera: Calliphoridae) Is a Primary Colonizer of Domestic Cats (Felis catus).

Lucilia silvarum Meigen (Diptera: Calliphoridae) is widespread throughout North America and Europe. Described in 1826, this blow fly was quickly associated with myiasis in amphibians, and to date has rarely been reported in carrion. There is limited data regarding the time of colonization of animals with fur and the interpretation of this data is difficult due to variation in the animal models used. During an examination of initial insect colonization of cats (Felis catus) with light and dark fur, twelve domestic short-haired cats were placed in cages 15.2 m apart in a grassy field in West Lafayette, Indiana, USA. Eggs from initial oviposition events were collected and reared to identify the colonizing species. Three species of Lucilia (Diptera: Calliphoridae), including L. silvarum, colonized the cats on the initial day of placement. In this study, L. silvarum was the primary colonizer of cats, and this may be the first study where a large number of L. silvarum were collected. Further studies should include development studies on L. silvarum to understand its life history and aid in time of colonization estimations. More work regarding the colonization of furred mammals is needed to further examine L. silvarum as a primary colonizer.

The gametogenic cycle of an invasive semelparous heterobranch sea slug from northern Patagonia, Argentina, reveals an annual lifespan

This study provides information about the reproductive cycle of the invasive side-gilled sea slug Pleurobranchaea maculata, currently widely distributed along the Argentine coast. The histological analysis of this simultaneous hermaphrodite showed characteristics of a semelparous species with an annual life cycle. The highest spermatogenic and oogenic activity was observed from August to January. Partial evacuations of mature oocytes, measuring over 100 μm in average diameter, occurred continuously during the long spawning season. Oviposition events started in winter and increased in frequency with increasing photoperiod (hours of light) until summer solstices. During February and March, post-reproductive and immature individuals coexisted, while mature individuals were rarely observed. These results represent important information on the reproductive patterns of an invasive species of worldwide ecological and sanitary concern.

Validation of enzyme immunoassays for quantifying sex steroid hormones in tropical screech owls (Megascops choliba)

Androgens and estrogens are steroid hormones that regulate reproductive processes in both males and females. Monitoring plasma levels of these steroids or their metabolites present in feces, offers diagnostic support for assessing the reproductive status of animals. Immunoassays are commonly used methods for quantifying these hormones, but their protocols require species-specific validation to ensure reliability. The objective of this study was to perform analytically and biologically validation of enzyme immunoassay (EIA) kits for measuring testosterone (T), estradiol (E2), faecal androgen metabolites (fAM), and faecal estrogenic metabolites (fEM) in the tropical screech owl (Megascops choliba). Serum and fecal samples were collected from six adult females and six males both before and during breeding season, with males' gonadal activity assessed using electroejaculation (EE). The parallelism test confirmed the immunogenic similarity of the antigens in the estradiol and testosterone standards and the antigens in the serum samples and fecal extracts of M. choliba. Additionally, the EIA kits displayed nearly 100% recovery rates, and showed coefficients of variation ranging from 8% to 14% at the intra-assay level and from 10% to 16% at the inter-assay level, underscoring result reliability and consistency. In males, the highest serum T and fAM levels were recorded concurrently with the presence of spermatozoa in samples collected via EE. Although females did not exhibit oviposition events, significantly higher E2 and fEM levels were observed in August compared to May, suggesting potential seasonal variations in estrogenic hormone production. Fecal androgen and estrogen levels were significantly different between sexes in August, with males having higher fAM and females having higher fEM levels. Overall, the immunoassays validated in this study were found to be efficient in diagnosing reproductive activity in owls.

Influence of the number of hosts and the risk of predation on the foraging behavior of the parasitoid Eretmocerus eremicus.

Parasitoids are natural enemies that can modify their behaviors as they search for hosts based on the characteristics of the sites in which they forage. Theoretical models predict that a parasitoid will stay for longer periods in high-quality sites or patches than in those of low quality. In turn, patch quality may be linked to factors such as the number of hosts and the risk of predation. In the present study, we sought to determine if the factors of the number of hosts, risk of predation, and their interaction influence the foraging behavior of the parasitoid Eretmocerus eremicus (Hymenoptera: Aphelinidae) as theory predicts. To do this, we evaluated different parameters of parasitoid foraging behavior, such as residence time, number of oviposition events, and attacks, in sites of different patch quality. Our results show that when the factors, number of hosts, and, risk of predation, were evaluated separately, E. eremicus resided for longer periods and oviposited more frequently in patches with a high number of hosts and low risk of predation than in other patches. However, when both of these factors were combined, only the number of hosts influenced some aspects of the foraging behavior of this parasitoid, such as the number of oviposition events and attacks. For some parasitoids like E. eremicus, theoretical predictions may be fulfilled when patch quality is linked to the number of hosts but will not be fully satisfied when patch quality is related to the risk of predation. Furthermore, at sites with different combinations of host numbers and risk of predation, host number appears to be more critical than predation risk. These results suggest that the performance of the parasitoid E. eremicus to control whiteflies will be mainly mediated by the levels of whitefly infestation and, to a small extent, by the risk of predation to which the parasitoid is subjected. © 2023 Society of Chemical Industry.

Protein- and Carbohydrate-Rich Supplements in Feeding Adult Black Soldier Flies (Hermetia illucens) Affect Life History Traits and Egg Productivity.

The black soldier fly, Hermetia illucens (BSF; Diptera: Stratiomyidae), has come into the focus of research over the past decade since its larvae are polyphagous feeders with an exceptional substrate range, making them a promising candidate for the bioconversion of various organic side streams into valuable insect protein. While larval nutritional requirements have been studied in detail, basic information on adult feeding is still lacking. The reproduction of adult flies is a bottleneck and key determinant in rearing BSF, which has extensive potential for improvement. In the present study, we examined the impact of different carbohydrate (honey and d-glucose) and protein sources (Spirulina and Chlorella powder) on a variety of life history traits using a highly standardized single pair approach. Feeding a 5% honey solution was shown to make females live 2.8 d longer, become more fecund (9 egg clutches per 10 females), lay more eggs (increasing 1.7-fold to 182.4 mg per 10 females), reduce the number of failed oviposition events 3-fold and increase multiple oviposition events from 2 to 15. Additionally, female longevity after oviposition improved 1.7-fold from 6.7 to 11.5 d. In order to further optimize adult feeding, mixtures of proteins and carbohydrates with varying ratios should be tested.

Assessment of Chestnut Gall Toughness: Implications for a Biocontrol Agent.

(1) Torymus sinensis, the biocontrol agent of the Asian chestnut gall wasp Dryocosmus kuriphilus, is univoltine, but in NW Italy a small percentage of individuals exhibits a prolonged diapause, mainly as late instar larva. (2) In 2020, the diapause was investigated to evaluate its trend over the years. Due to the low survival rate of diapausing T. sinensis adults, the seasonal variation in the galls' toughness was evaluated, thus assuming that dry galls over time can negatively affect emergence. The window of vulnerability of the gall wasp galls was also evaluated in controlled conditions. (3) The results showed that the average number of second year T. sinensis emerging per 100 cells was 0.41 ± 0.05, and dead adults accounted for 4.1 ± 0.23 per 100 cells. Gall toughness resulted in lower values for galls collected in May and June, and then gradually increased over time. In general, no difference was detected in the wall toughness of galls formed during the previous year when compared to current-year dry galls. Oviposition was recorded on all the tested galls collected in May and June, and no difference in the number of oviposition events was detected. Conversely, no oviposition was observed in July. Comparing the number of oviposition events by T. sinensis and the gall toughness, a negative correlation was found (R2 = -0.99). (4) The present findings contribute descriptive information on this gall's structural traits, and the influence on gall wasp management is also discussed.

A new model formulation for host depletion in parasitoids

A new model of host depletion in the functional response of parasitoids is presented. Most existing models describe the dynamics of prey consumption as a sequential-memoryless/Markovian process of searching for, handling, and consuming prey, but the feeding interaction between a parasitoid and its host is different. One of the most important characteristics is that the host is not consumed, and remains in the arena. On the other hand, functional response models of solitary parasitoids assume that each host can accommodate an infinite number of oviposition events without being killed or becoming unsuitable as a host without the parasitoid noticing it. As a consequence, host depletion is never considered in parasitoid functional response models. To solve that issue, we extended the traditional random predator and random parasitoid functional response models of Rogers into a compartmental model formulated with ordinary differential equations, to group hosts with a different number of attacks to simulate how the parasitoid spreads the attacks between already parasitized and non-parasitized hosts. This model was further modified to simulate non-sequential memoryless search, handling and oviposition. We studied the behaviour of these models to understand how a variation of their parameters led to different shapes of functional response curves and statistical distributions of the number of parasitoid eggs laid per host. The results showed that the expected curves differ from those predicted by the simpler Holling's disk equation (type II functional response), random parasitoid models (no depletion), and the random predator model (proportional depletion). Finally, the non-sequential-memoryless models predict straight curves resembling a type I functional response at low host densities.

Field and Laboratory Efficacy of Low-Impact Commercial Products in Preventing Olive Fruit Fly, Bactrocera oleae, Infestation.

Simple SummaryThe adoption of sustainable methods for herbivore pest control has become mandatory in Europe, with the EU directive 128/09. Since then, stringent evaluation protocols have been applied to insecticides and several molecules (that are suspected to be unsafe for the environment or human health) have been banned. Hence, the evaluation of sustainable methods, e.g., preventive tools based on the manipulation of pest behaviour, must be considered. Using field and laboratory assays, we tested the efficacy of different products in preventing infestation of a key pest of olive orchards, the olive fruit fly Bactrocera oleae. Our findings may be useful for the development of control strategies in integrated pest management (IPM) and organic agriculture.The olive fruit fly, Bactrocera oleae, is the key pest of olive trees in several areas of the world. Given the need for the development of sustainable control methods, preventive tools, based on the manipulation of pest behaviour, must be considered. Here, under field and laboratory conditions, we tested the efficacy of different products in preventing B. oleae infestation. A field trial was conducted, from July to November 2020, in an olive orchard located in Central Italy. A table olive variety was selected and sprayed with rock powder, propolis, the mixture of both, copper oxychloride, or water (control). All treatments, except propolis, caused a reduction of B. oleae oviposition in olives, compared to the control. The mixture allowed the strongest reduction of fly infestation throughout the season, suggesting a synergistic effect. Behavioural no-choice assays were conducted to better understand the effects of treatments on B. oleae females. Compared to the control, females showed a lower preference for the central area of an arena containing an olive twig bearing two olive fruits, fully developed, but still green, treated with rock powder, plus propolis mixture. For all treatments, B. oleae showed lower oviposition events, suggesting deterrence to oviposition. Our results indicate that the tested products may have value against B. oleae, within integrated pest management (IPM) and organic agriculture.

How do gulls synchronize every-other-day egg laying?

Increased sea-surface temperatures lead to increased egg cannibalism in Glaucous-winged Gulls (Larus glaucescens). Under these conditions, female gulls, which lay an egg approximately every 2 d, can synchronize egg laying with other females on an every-other-day schedule. Eggs that are laid synchronously are less likely to be cannibalized. The mechanism for synchronization has remained unknown. We studied the relationship between egg laying and mounting in a colony of Glaucous-winged Gulls on Protection Island, Washington, for clues to a synchronizing mechanism. We found that for an individual female an oviposition event reduced the likelihood of mounts for that day as compared to the day before, and that for sampled areas of the colony, total numbers of mounts and eggs laid occurred in an out-of-phase rhythm. These findings support the following conceptual model: early in the breeding season, individual females that have begun laying exhibit a daily alternation of higher and lower mounting activity caused by their natural 2 d oviposition oscillation. By social facilitation, these mounting oscillations of early layers synchronize mounting across the colony, including mounting events involving females that are not yet laying. Mount synchronization eventually leads to every-other-day egg laying synchronization.

Multi-Omic Analysis of Symbiotic Bacteria Associated With Aedes aegypti Breeding Sites.

Mosquito breeding sites are complex aquatic environments with wide microbial diversity and physicochemical parameters that can change over time during the development of immature insect stages. Changes in biotic and abiotic conditions in water can alter life-history traits of adult mosquitos but this area remains understudied. Here, using microbial genomic and metabolomics analyses, we explored the metabolites associated with Aedes aegypti breeding sites as well as the potential contribution of Klebsiella sp., symbiotic bacteria highly associated with mosquitoes. We sought to address whether breeding sites have a signature metabolic profile and understand the metabolite contribution of the bacteria in the aquatic niches where Ae. aegypti larvae develop. An analysis of 32 mosquito-associated bacterial genomes, including Klebsiella, allowed us to identify gene clusters involved in primary metabolic pathways. From them, we inferred metabolites that could impact larval development (e.g., spermidine), as well as influence the quality assessment of a breeding site by a gravid female (e.g., putrescine), if produced by bacteria in the water. We also detected significant variance in metabolite presence profiles between water samples representing a decoupled oviposition event (oviposition by single females and manually deposited eggs) versus a control where no mosquito interactions occurred (PERMANOVA: p < 0.05; R2 = 24.64% and R2 = 30.07%). Five Klebsiella metabolites were exclusively linked to water samples where oviposition and development occurred. These data suggest metabolomics can be applied to identify compounds potentially used by female Ae. aegypti to evaluate the quality of a breeding site. Elucidating the physiological mechanisms by which the females could integrate these sensory cues while ovipositing constitutes a growing field of interest, which could benefit from a more depurated list of candidate molecules.

Host utilization by the pepper weevil (Anthonomus eugenii): suitability, preference and offspring performance.

Host plant selection is a key factor affecting the survival, population establishment, and spread of herbivorous insect pests. The pepper weevil is one of the most important pests of cultivated pepper in North America with a capacity to rapidly expand its geographic range, in part through its ability to switch between cultivated and wild Solanaceous host plants. Towards a better management of this pest, this study examined metrics of pepper weevil host use including oviposition preference, development time, and successful offspring emergence on wild Solanaceous species and cultivated pepper cultivars. Pepper weevil successfully developed within fruit of several Solanaceous species including eastern black (Solanum ptycanthum) and climbing nightshade (S. dulcamara), in which development time was on average 4 days faster relative to Capsicum annuum cv. jalapeno peppers. Oviposition events occurred in all fruit types assessed and no strong host preference was detected among these. However, the number of emerged offspring was significantly lower than the number of oviposition events in C. chinense cv. habanero pepper fruit. Although not all nightshade species are suitable hosts for pepper weevil development, those permissive to offspring production do allow for faster development than in C. annuum peppers. While host preference was not detected among fruit types tested, low offspring emergence from fruit with high capsaicin content suggests a reduced ability of pepper weevil to tolerate high concentrations of this metabolite. These findings help elucidate the factors influencing pepper weevil bionomics, and their implications on pepper weevil management are discussed. Published 2021. This article is a U.S. Government work and is in the public domain in the USA.

Life history of the Big Sandy crayfish Cambarus callainus Thoma, Loughman &amp; Fetzner, 2014 (Decapoda: Astacoidea: Cambaridae), an imperiled crayfish in the central Appalachian coalfields, USA

AbstractThe Big Sandy crayfish, Cambarus callainusThoma, Loughman &amp; Fetzner, 2014, endemic to the Big Sandy River basin in the central Appalachians, USA, was listed by the United States Fish &amp; Wildlife Service as threatened under the Endangered Species Act in 2016 due to limited and declining range. In March 2018 we began a twelve-month study of the species at the Dry Fork watershed in West Virginia, USA and the Russell Fork watershed in Virginia, USA to document annual life history, reveal if seasonal molting occurs, determine the reproductive season and fecundity, and define its life history strategy. Egg-bearing females were only captured in August; however, a single female was collected with free-living craylings in April, suggesting possible overwintering maternal care or a potential early spring oviposition event. Mating likely occurred between May and June and potentially into the fall and early winter. Five to six size-class cohorts were observed, and we speculate that C. callainus could live up to five years or more. Analysis of morphometric data suggests that females undergo form change, displaying larger chelae and wider abdomens. The smallest Form I male collected had a total carapace length (TCL) of 31.5 mm and the smallest Form I female 32.8 mm. The largest male collected was Form I with a TCL of 55.9 mm. Similar to other species of Cambarus, C. callainus appears to exhibit K-selected life history traits: Fewer and larger eggs, relatively longer maternal care, larger but slow growing, and long lived. The life history information described should prove invaluable to those engaging in conservation efforts for this threatened species.

Using an artificial neural network to predict the probability of oviposition events of precision-fed broiler breeder hens

Identifying daily oviposition events for individual broiler breeders is important for bird management. Identifying non-laying birds in a flock that might be caused by improper nutrition or diseases can guide diet changes or disease treatments for these individuals. Oviposition depends on follicle maturation and egg formation, and follicle maturation can be variable. As such, the day and time of oviposition events of individual birds in a free-run flock can be hard to predict. Based on a precision feeding (PF) system that can record the feeding activity of individual birds, a recent study reported a machine learning model to predict daily egg-laying events of broiler breeders. However, there were 2 limitations in that study: 1) It could only be used to identify daily egg-laying events on a subsequent day; 2) The prediction outputs that were binary labels were unable to indicate more details among the outputs with the same label. To improve the previous approach, the current study aimed to predict and output the probability of daily oviposition events occurring using a specific time point in 1 day. In the current study, 706 egg-laying events recorded by nest boxes with radio frequency identification of hens and 706 randomly selected no-egg-laying events were used. The anchor point was newly defined in the current study as a specific time point in 1 day, and 26 features around the anchor point were created for all events (706 egg-laying events and 706 no-egg-laying events). A feed-forward artificial neural network (ANN) model was built for prediction. The area under the receiver operating characteristic (ROC) curve was 0.9409, indicating that the model had an outstanding classification performance. The ANN model could predict oviposition events on the current day, and the output was a probability that could be informative to indicate the likelihood of an oviposition event for an individual breeder. In situations where total egg production was known for a group, the ANN model could predict the probability of daily oviposition events occurring of all individual birds and then rank them to choose those most likely to have laid an egg.

First Record of Panoquina panoquin (Salt Marsh Skipper) Ovipositing on Spartina alterniflora (Smooth Cordgrass)

Panoquina panoquin (Salt Marsh Skipper) is an understudied butterfly that resides primarily in coastal salt marshes throughout the southern Atlantic and Gulf of Mexico. Based on our review of online databases and published literature, this species may use several different host plants, though Distichlis spicata (Saltgrass) is most commonly cited. While surveying salt marsh butterfly communities in southeastern Virginia in 2019, we observed 25 oviposition events from female Salt Marsh Skippers, all of which laid their eggs exclusively on Spartina alterniflora (Smooth Cordgrass). This is the first conclusive record of the Salt Marsh Skipper using this species of grass for egg laying. Our observations broaden the understanding of Salt Marsh Skipper habitat requirements and therefore inform conservation efforts for this species in the face of degradation of salt marshes throughout its range.

Application of random forest classification to predict daily oviposition events in broiler breeders fed by precision feeding system

In group-housed poultry, hormone and environment modulated variability in the processes of follicle maturation and egg formation make it difficult to predict a daily egg-laying event (oviposition). Recording daily egg laying events has required individual cages or expensive technology such as RFID equipped nests or labor intensive trap nests. The current study implemented the random forest classification algorithm to predict oviposition events of 202 free run Ross 708 broiler breeder hens fed by a precision feeding system from week 21 to 55, based on a dataset recording information of all visits to the station. The raw dataset from the precision feeding system was processed for 6 classes of features (34 features in total) in relation to feeding activity and real-time body weight of birds. The dataset of the features was then combined with a corresponding daily individual oviposition record. The processed data were shuffled and separated into 2 subsets: 90% for training, and 10% for testing. Important features were selected using random forest-recursive feature elimination with 5-fold cross-validation, and 28 features were selected to build a random forest classification model. Overall accuracy of the model using the testing samples was 0.8482, and out-of-bag score was 0.8510. Precision (a measure of purity in retrieving) of no egg-laying and egg-laying, recall (a measure of completeness in retrieving) of no egg-laying and egg-laying were 0.8814, 0.8090, 0.8520 and 0.8453, respectively. The Kappa coefficient of the model was 0.6931, indicating substantial agreement (substantial agreement range: 0.61–0.80). This model was able to identify whether a free run broiler breeder laid an egg or not on a certain day during the laying period with around 85% accuracy.

Characterization of the Volatiles' Profiles of the Eggs of Forensically Relevant Lucilia sericata and Phormia regina (Diptera: Calliphoridae) Blow Flies by SPME-Facilitated GC-MS.

The attraction of necrophagous insects, particularly blow flies, to corpses and carrion is of ecological, economic, and agricultural importance, although the mechanisms by which it occurs are not well understood. Much of the published research on blow fly attractants has focused on volatiles emitted from carrion surrogates, but little attention has been given to the possibility that blow fly eggs themselves may emit chemical cues that are responsible for conspecific and heterospecific insect attraction. In this study, the headspace volatiles emitted from eggs representing two aggregated oviposition events that were collected 1 mo apart from two species of the Calliphoridae family (Order: Diptera), Lucilia sericata (Meigen), and Phormia regina (Meigen) were analyzed via solid-phase microextraction-facilitated GC-MS. The volatiles' profiles were found to be consistent between samples representing the same species, but unique between the two species. Over 100 molecules covering a wide range of compound classes that included alcohols, aldehydes, esters, amines, ketones, and organosulfur compounds were identified. The profile of volatiles emitted from the L. sericata eggs contained several alkanes and aldehydes, whereas salient features of the P. regina headspace included numerous esters and ketones. Between the two species, 42 compounds were shared, several of which were carboxylic acids. Little overlap between the range of compounds detected and those reported to be emitted from decomposing remains was observed.