Consumption Of Plant Material Research Articles

Diet of the Invasive Atlantic Blue Crab Callinectes sapidus Rathbun, 1896 (Decapoda, Portunidae) in the Guadalquivir Estuary (Spain)

The Atlantic blue crab Callinectes sapidus (Decapoda, Portunidae) Rathbun, 1896 is native to the east coasts of North and South America and has recently expanded its distribution in the non-native range into the Gulf of Cadiz (SW Iberian Peninsula, Europe). Considering the impacts caused by this invasive species in numerous estuarine ecosystems and its generalist feeding behavior, this study aims to provide the first account of the Atlantic blue crab diet on the East Atlantic coast. We studied the species’ feeding habits using stomach content analyses to predict food web interactions and putative impacts. Samples were obtained in the Guadalquivir estuary (SW Spain, Europe), which was colonized in 2017. The main food items identified on their stomach were, fish (49.9%), mollusks (44.4%) and crabs (32.3%). They also consumed plant material (27.2%), and the sediment (32.3%) in their digestive tract was likely the result of secondary ingestion. The Atlantic blue crab exhibited the same omnivorous behavior as in the native area. There was no sexual variation in diet composition or feeding activity in general, but there was a seasonal variation in the diet composition of females. The decrease of the caramote prawn Penaeus kerathurus (Forskål 1775) observed in the Guadalquivir estuary since 2021 is likely not due to the Atlantic blue crab because they seldomly eat this prey. Overall, our study provides clear baseline information to expand the knowledge about the ecological roles of the Atlantic blue crab in non-native ecosystems.

Comparative analyses of the banded alder borer (Rosalia funebris) and Asian longhorned beetle (Anoplophora glabripennis) genomes reveal significant differences in genome architecture and gene content among these and other Cerambycidae.

Rosalia funebris (RFUNE; Cerambycidae), the banded alder borer, is a longhorn beetle whose larvae feed on the wood of various economically and ecologically significant trees in western North America. Adults are short-lived and not known to consume plant material substantially. We sequenced, assembled and annotated the RFUNE genome using HiFi and RNASeq data. We documented genome architecture and gene content, focusing on genes putatively involved in plant feeding (phytophagy). Comparisons were made to the well-studied genome of the Asian longhorned beetle (AGLAB; Anoplophora glabripennis) and other Cerambycidae. The 814Mb RFUNE genome assembly was distributed across 42 contigs, with an N50 of 30.18Mb. Repetitive sequences comprised 60.27 % of the genome, and 99.0 % of expected single-copy orthologous genes were fully assembled. We identified 12657 genes, fewer than in the four other species studied, and 46.4 % fewer than for Aromia moschata (same subfamily as RFUNE). Of the 7258 orthogroups shared between RFUNE and AGLAB, 1461 had more copies in AGLAB and 1023 had more copies in RFUNE. We identified 240 genes in RFUNE that putatively arose via horizontal transfer events. The RFUNE genome encoded substantially fewer putative plant cell wall degrading enzymes than AGLAB, which may relate to the longer-lived plant-feeding adults of the latter species. The RFUNE genome provides new insights into cerambycid genome architecture and gene content and provides a new vantage point from which to study the evolution and genomic basis of phytophagy in beetles.

Struggling to survive: A comparison of Vanessa cardui larval survivorship on putative host plants

AbstractThe painted lady butterfly (Vanessa cardui) is a generalist herbivore with a global distribution. In North America, over 100 species have been identified as V. cardui larval host plants. This cosmopolitan species is commercially available in all life stages and can be reared on an artificial diet. As a result, V. cardui commonly serves as a model organism for education and outreach. However, gaps in our knowledge remain with regard to V. cardui ecology and larval host plant suitability for supporting complete development of larvae to reproductive adulthood. In a laboratory setting, we tested host plant suitability of five reported host plants commonly found in California sage scrub ecosystems by assessing survival of V. cardui caterpillars in its entirety. We also assessed how commercially sourced larvae survived on artificial diet: both raising the caterpillars exclusively on artificial diet as well as switching diets from artificial to thistle (a commonly reported host plant) and switching from thistle to artificial diet. We found that all commercially sourced caterpillars exhibited both high larval mortality and low pupation rates when reared on host plants, although larvae reared on Malacothamnus fasciculatus and Sphaeralcea ambigua survived longest. Moreover, M. fasciculatus and S. ambigua were the only host plants tested that supported successful pupation. This contrasted with 63% higher survival of wild‐collected larvae. Our findings suggest that commercially obtained V. cardui may struggle to utilize wild host plants and that future investigations into host plant suitability in wild populations are needed. Additionally, future research using commercial larvae should consider the implications for interpreting host plant suitability as larvae may exhibit adaptations to artificial diet or the loss of adaptation to consuming plant material.

Evolution of postcanine complexity in Gomphodontia (Therapsida: Cynodontia).

Gomphodonts form a Triassic radiation of small to medium-bodied (<0.5-2.5 m in length) quadrupedal cynodonts characterized by labiolingually expanded gomphodont postcanines. They were the dominant cynodont group in Middle and Late Triassic ecosystems from the Southern Hemisphere and the first predominantly herbivorous cynodonts to evolve. Gomphodonts were also the first therapsids to develop hypsodonty and a dentition with complex occlusal patterns, and their highly diagnostic upper and lower postcanines show many different morphologies. Here, we explored dental complexity in gomphodont cynodonts through time using geographic information system analysis and orientation patch count applied on 3D crown surfaces of upper and lower gomphodont postcanines belonging to 32 gomphodont taxa. This study reveals that the peak in postcanine complexity was reached early in the evolution of gomphodonts with the emergence in the Early Triassic of omnivorous or insectivorous forms with postcanines made of well-separated cusps and cingular cuspules. Traversodontids evolved simpler postcanines via coalescence of cusps into crests and the development of large occlusal basins, and the Middle Triassic radiation of traversodontids led to a sharp decrease in mean postcanine complexity. Simplification of the postcanines in traversodontids is interpreted as being related to a gradual increase in the consumption of plant material. Interestingly, the trend of insectivory/omnivory high postcanine complexity and herbivory low dental complexity in gomphodonts is opposite to the trend of dental complexity reported in some extant mammals, with omnivorous having low dental complexity and herbivorous higher. Postcanine complexity remained relatively stable throughout the evolution of traversodontids and only slightly diminished in the Late Triassic due to the presence of minute forms with particularly simple postcanines in the Rhaetian. The major phylogenetic diversity and taxonomic richness of Gomphodontia are represented in two periods of time: at the end of the Anisian, an age in which the postcanine complexity is simplifying, and at the early Carnian when the postcanine complexity in traversodontids, the only Gomphodontia represented, is stable.

The Roman snail (Gastropoda: Helicidae) is not a generalist herbivore, but shows food preferences for Urtica dioica and plant litter

ABSTRACT The food preferences and palatability of different plant species for snail and slug species in arable fields has been a major area of research in the past. The assumed diet of Helix pomatia (Linnaeus, 1758), however, provides an example of the limited knowledge of snail diets in nonagricultural habitats. This species has been described as a generalist herbivore, although it showed preferences for individual plant species in another study. Helix pomatia is considered a pest species, while also being listed as endangered in several Red Lists. In this study, the feeding activity of eight subpopulations of H. pomatia were recorded in a nature reserve in Cottbus, Germany, from April to October 2021 to understand food preferences and feeding behaviour. Along with the plant species on which feeding was observed, the height of feeding in the vegetation, shell width and height, number of whorls, and exposure to direct sunlight at observation sites were recorded. Results indicate that H. pomatia prefers Urtica dioica, and plant litter, which accounted for 35% and 44% of all observed feeding interactions respectively, as food resources, while generally only feeding on 27 of 143 available plant species. The importance of U. dioica as a food resource for 19 other terrestrial snail species is confirmed by 18 previous studies. In H. pomatia, analysis of the width and height of shells indicated that smaller, juvenile snails consumed plant material significantly higher up in vegetation as compared to adult snails, which fed closer to the ground. Awareness of the preference in H. pomatia for U. dioica as a food resource may be beneficial for land managers regarding the impact of this snail as an agriculture pest to crops. Urtica dioica is a very important food plant for terrestrial snails, and could play an important role in future species conservation strategies.

Associative colour learning and discrimination in the South African Cape rock sengi Elephantulus edwardii (Macroscelidea, Afrotheria, Mammalia)

Abstract Beside insects, sengis also consume plant material such as leaves, fruits, seeds and floral nectar. It is known that they use olfaction for foraging, but little is known about their vision and visual learning capabilities. Colour vision has been tested in two species, showing that they are likely dichromats (green- and blue-sensitive retinal cone-photoreceptors, meaning red-green colour blind). Our aim was to examine the learning and colour discrimination abilities of another species, Elephantulus edwardii. Using training procedures and choice experiments, we tested the hypotheses that the animals can associate a reward with trained colours and that they can discriminate between different colour hues. The sengis preferred the trained colours over the others, indicating associative learning. They could discriminate between all tested colours (blue, red, green, yellow). The sengis’ colour choice behaviour indicates that the animals can use also colour features to find food plant material. Additionally, learning abilities most likely are essential for the sengis’ foraging activities, for instance by associating floral or fruit shape, colour or scent with nectar or ripe fruit, to increase the efficiency to locate food sources.

03.Diet composition and tropic niche overlap of Ameivula ocellifera Spix 1825 (Squamata: Teiidae) and Tropidurus cocorobensis Rodrigues 1987 (Squamata: Tropiduridae), sympatric species with different foraging modes, in Caatinga

Lizard diets can be influenced by several factors, such as age, physiological aspects, food availability, behaviour and foraging mode. The latter can be an important predictor of the type of prey consumed. This study analysed Ameivula ocellifera and Tropidurus cocorobensis diets, both of which are psammophiles and coexist in an area of Caatinga in north-eastern Brazil, but use different foraging modes. Lizard stomachs were examined, and prey categories were quantified by frequency of occurrence, number, volume and relative importance index. We used PERMANOVA and SIMPER analyses to understand the dissimilarities among diets. Additionally, we estimated the degree of trophic niche overlap between species using the Pianka index. The most frequently consumed food item by A. ocellifera was Isoptera and Formicidae (Hymenoptera) for T. cocorobensis. The trophic niche overlap between the species was approximately 0.24 and, although there were many consumed prey categories in common, the proportion at which these prey categories were consumed was quite divergent. For example, the consumption of plant material, which was present in the diet of both species, was much more important for T. cocorobensis compared to the active forager A. ocellifera. Our results indicate that despite sharing the same space and consuming the same prey types, these species have significant differences in their diets. Furthermore, these divergences can be explained by several factors in the environment and even by the evolutionary history of each species, which are included in different families and are not evolutionarily close to each other. Keywords: diet; niche overlap; foraging mode; plant consumption; competition

Heavy metal wombats? Metal exposure pathways to bare-nosed wombats (Vombatus ursinus) living on remediated tin mine tailings

Rehabilitation of disused mine sites through stabilisation and botanical restoration is ecologically important, but metal transfer pathways to colonising wildlife are often less understood and have never been studied in marsupials. The rehabilitated Royal George tin mine tailings (Tasmania, Australia) and colonisation by bare-nosed wombats (Vombatus ursinus) represented an opportunity to examine potential metal transfer from mine tailings to an herbivorous marsupial. The aim of this study was to examine metal transfer pathways from the mine tailings to wombats, and to determine if wombats are at risk from metal exposure. Concentrations of metals were measured in the tailings substrate, surface water and vegetation, as well as fur samples from a resident wombat, and non-resident (control) wombats. The mineralogy of the tailings is dominated by quartz, muscovite, feldspars, topaz, kaolinite and calcite. Concentrations of several metals were high (exceeding varying health standards) in the tailings (As, Cu, Hg, Pb, Ni, Zn), water (As, Cd, Cu, Zn) and vegetation (As, Cd, Cu, Pb, Mn, Zn). Relative to non-resident wombats, elevated levels of As, Cd, Cu, Pb and Sn were measured in the fur of a resident wombat. Based on modelling of the exposure pathways, consumption of plant material is the most likely metal transfer pathway for As, Cu and Pb, although the risks from ingestion of tailings to this fossorial marsupial should not be discounted. This study is the first to investigate metal exposure pathways to marsupials using rehabilitated mine tailings. Further research is needed to accurately quantify ecological risks and toxicity for wombats and other marsupials native to mining landscapes.

Form and function of the feeding apparatus of sirenid salamanders (Caudata: Sirenidae): Three-dimensional chewing and herbivory?

Herbivory, and thus, the ability to acquire energy from consuming plant material, evolved numerous times independently within vertebrates. Several mechanical solutions for processing plant material have emerged along with the independent rise of herbivorous feeding strategies. Comparative studies of these mechanical solutions suggest that herbivory might generally relate to “improved” and hence comparatively effective food processing mechanisms, often involving the jaws. Such processing behaviours involving the jaws can be referred to as chewing sensu lato. While herbivory is relatively common among vertebrates, it is generally believed that salamanders exclusively feed on other animals (i.e., carnivory). Further, it had been hypothesized that salamander food processing is limited to “simple” and comparably ineffective puncture crushing movements (i.e., opening and closing movements of the jaws in combination with pointed teeth), which may not be efficient enough to break down plant material. However, sirenid salamanders (i.e., dwarf sirens and sirens, genera Pseudobranchus and Siren respectively) have long been reported to consume large amounts of plant material besides feeding on animal prey. Additionally, some sirenids have only recently been shown to apply complex three-dimensional chewing behaviours. These complex chewing behaviours could potentially enable the mechanical breakdown of plant material. Here we comparatively study sirens with particular regards to the form and function of their feeding apparatus and their feeding habits. We demonstrate that sirenids generally seem to apply complex chewing mechanisms and, in fact, consume both plant- and animal foods. Comparative gastrointestinal morphology, however, suggests that among sirenids, only sirens are apt to digest and extract energy from plant material, suggesting that dwarf sirens may not benefit from the energy of their “plant food”, while sirens appear to be facultative herbivorous - or better, omnivorous. Consequently, our results indicate that some salamanders can eat, process, and acquire energy from plant material, hence, contradicting the commonly accepted idea that salamanders are generally carnivorous.

Dietary affinities, resource overlap and core structure in Atlantic Forest phyllostomid bat communities

Abstract The Phyllostomidae is arguably the most diverse family‐level clade of mammals. Associated with this high diversity is considerable heterogeneity in resource utilisation among species and across locales of the Neotropics. Despite heterogeneity, few attempts have been made to synthesise dietary patterns even for smaller regions within the Neotropics. Atlantic Forest is a large dynamic ecoregion in the southern Neotropics that is distinct from other Tropical forests because of its extensive latitudinal extent, elevated climatic heterogeneity, biodiversity and long history of anthropogenic modification. I obtained data on dietary affinities of 34 species of bats from 35 different sites spanning the entire Atlantic Forest. In Atlantic Forest, as in other places in the Neotropics, phyllostomids consumed arthropods, vertebrates, fruits, nectar and blood. Frugivores consumed and dispersed the fruits of 99 different species of plants and nectarivores pollinated an additional nine others. Dietary overlap was modest, yet significantly greater than expected based on a null model. The main axis of variation in diet separated species that primarily consumed animal material from those that primarily consumed plant material and this axis was significantly related to phylogenetic affinities of species. Unlike in other places in the Neotropics, frugivorous bats did not exhibit a core structure related to genus‐to‐genus matching of bat genera with plant genera. Generality of diets of frugivorous bats, further indicated by non‐randomly high dietary overlap, is likely to degrade core structure in these primarily Subtropical communities. Co‐occurrence of a large number of generalist bat species, seasonal climates and ubiquitous anthropogenic modification may serve to promote generality of resource utilisation of bats in Atlantic Forest. The Neotropics is vast and the bats that live within it are diverse. Future studies should explore spatial dynamics of dietary affinities and resource overlap to increase understanding of the context of strong and weak core structure of phyllostomid bat communities.

Frequent consumption of sap suggests that omnivory is widespread among Australian geckos.

The diets of many animals are influenced by resource availability, competition, and evolutionary selected traits enabling the utilization of palatable foods. Omnivores are species that maintain their macronutrient balance by supplementing highly abundant but poor nutritional quality food items, with sporadically available but high nutritional quality food items. Although there are anecdotal observations of Australian geckos (Lacertilia: Gekkonidae) consuming plant exudates, the consumption of plant material has long been considered to be anomalous behavior among Australian geckos. Here, we test the idea that sap feeding may not be anomalous behavior but instead a dietary niche of geckos that has gone unappreciated due to constraints on the methods used to quantify geckos' diets. We tested this idea by investigating the consumption of Acacia victoriae gum by the gecko Gehyra versicolor using timed searches and time-lapse photography. We found that geckos frequently consumed gum, and G. versicolor numbers were five times greater on A. victoriae trees that exhibited significant gum bleeds compared to gecko numbers on non-bleeding trees. Taken together, our observations that G. versicolor spp. frequently feed on gum along with anecdotal reports of geckos consuming gum provide compelling evidence that gum/sap feeding is not anomalous behavior and suggest that many Australian gecko species are omnivores whose diets include plant exudates and animal prey.

Selenium Application During Radish (Raphanus sativus) Plant Development Alters Glucosinolate Metabolic Gene Expression and Results in the Production of 4-(methylseleno)but-3-enyl glucosinolate.

Selenium (Se) is an essential micronutrient for human health, entering the diet mainly through the consumption of plant material. Members of the Brassicaceae are Se-accumulators that can accumulate up to 1g Se kg−1 dry weight (DW) from the environment without apparent ill effect. The Brassicaceae also produce glucosinolates (GSLs), sulfur (S)-rich compounds that benefit human health. Radish (Raphanus sativus) has a unique GSL profile and is a Se-accumulating species that is part of the human diet as sprouts, greens and roots. In this report we describe the effects of Se-fertilisation on GSL production in radish during five stages of early development (from seed to mature salad greens) and on the transcript abundance of eight genes encoding enzymes involved in GSL metabolism. We tentatively identified (by tandem mass spectrometry) the selenium-containing glucosinolate, 4-(methylseleno)but-3-enyl glucosinolate, with the double bond geometry not resolved. Two related isothiocyanates were tentatively identified by Gas Chromatography-Mass Spectrometry as (E/Z?) isomers of 4-(methylseleno)but-3-enyl isothiocyanate. Se fertilisation of mature radish led to the presence of selenoglucosinolates in the seed. While GSL concentration generally reduced during radish development, GSL content was generally not affected by Se fertilisation, aside from the indole GSL, indol-3-ylmethyl glucosinolate, which increased on Se treatment, and the Se-GSLs, which significantly increased during development. The transcript abundance of genes involved in aliphatic GSL biosynthesis declined with Se treatment while that of genes involved in indole GSL biosynthesis tended to increase. APS kinase transcript abundance increased significantly in three of the four developmental stages following Se treatment. The remaining genes investigated were not significantly changed following Se treatment. We hypothesise that increased APS kinase expression in response to Se treatment is part of a general protection mechanism controlling the uptake of S and the production of S-containing compounds such as GSLs. The upregulation of genes encoding enzymes involved in indole GSL biosynthesis and a decrease in those involved in aliphatic GSL biosynthesis may be part of a similar mechanism protecting the plant’s GSL complement whilst limiting the amount of Se-GSLs produced.

Guaiacol oxidation activity of herbivorous land crabs, Chiromantes haematocheir and Chiromantes dehaani

The land crabs, Chiromantes haematocheir (Akate-gani) and Chiromantesdehaani (Kurobenkei-gani) inhabit seaside forests in Japan. The crabs mainly consume plant material and its detritus. Therefore, they are expected to possess the ability to degrade the major components of biomass, cellulose and lignin in order to digest plant materials. In this study, we analyzed biomass-degrading activities of the land crabs, especially guaiacol oxidation activity, which seems to be related to lignin degradation. Cellulase activity was detected from almost all gut samples including the stomach, midgut gland and intestine of all dissected crabs. Conversely, high guaiacol oxidation activity was detected in the midgut gland of all C.dehaani and several female C.haematocheir crabs. This is consistent with a previous study showing that female crabs were more herbivorous than male crabs were and observation that C.dehaani crabs are more herbivorous than C.haematocheir. Guaiacol oxidation activity might play an important role in the herbivorous behavior of land crabs.

Metabolic analysis of the melatonin biosynthesis pathway using chemical labeling coupled with liquid chromatography-mass spectrometry.

Characterization of the melatonin (MLT) biosynthesis pathway in plants is still limited. Additionally, a metabolomic analysis of MLT biosynthesis in plants is still a challenge due to analyte structural and chemical diversity, low analyte abundances, and plant matrix complexities. Herein, a sensitive liquid chromatography-mass spectrometry (LC-MS) method enabling the simultaneous determination of seven plant MLT biosynthetic metabolites was developed. In the proposed strategy, the targeted metabolites, which included tryptophan (Trp), tryptamine (TAM), 5-hydroxytryptophan (5HTP), serotonin (5HT), N-acetylserotonin (NAS), 5-methoxytryptamine (5MT), and MLT, were purified from plant extracts using a one-step dispersive solid-phase extraction (DSPE). The samples were then chemically labeled with dansyl chloride (DNS-Cl), followed by analysis using LC-MS. The limit of detection (LOD) values ranged from 0.03 to 1.36pg/mL and presented a 22- to 469-fold decrease when compared to the unlabeled metabolites. Due to the high sensitivity of the proposed method, the consumption of plant materials was reduced to 10mg FW. Ultimately, the established method was utilized to examine the distributions of MLT and its intermediates in rice shoots and roots with or without cadmium (Cd) stress. The results suggested that under normal condition, MLT may also be generated via a Trp/TAM/5HT/5MT/MLT path (Pathway II) in addition to the previously reported Trp/TAM/5HT/NAS/MLT path (Pathway I), although Pathway I was shown to be dominant. During Cd stress, MLT was also shown to be produced through these two pathways, with Pathway II shown to be dominant in rice shoots and roots.

Medieval animal management practices at Proezzhaia I: Insights from dietary stable isotope analysis

In this paper, we report the stable carbon and nitrogen isotope analysis results of wild (n = 15) and domestic (n = 21) animal samples from the Proezzhaia I site, a fortified Medieval settlement in Trans-Baikal, Siberia. Additionally, we analyzed five modern freshwater fish samples from the Shilka River, which flows immediately north of the site. Together, these samples provide the first dietary stable isotope data for the entire Trans-Baikal region. Our results reveal a C3 plant dominated diet for all animal taxa sampled, but with a possible minor inclusion of C4 plant material in the diets of some cattle (Bos sp.) and horses (Equus sp.). We infer this C4 plant was likely a type of millet, the remains of which were identified at a contemporaneous site upriver. Additionally, these results indicate that some cattle and horses consumed plant material grown in 15N-enriched soil, which suggests several distinct animal management practices, or may indicate a trade in or movement of animals from an area with a different nitrogen isotope baseline.

The Effect of Aerobic Training and Green Tea Supplementation on Cardio Metabolic Risk Factors in Overweight and Obese Females: A Randomized Trial.

BackgroundThe use of exercise along with green tea supplements has been shown to have beneficial effects on obesity and its complications.ObjectivesThis study aimed at exploring the effect of aerobic training (AT) and green tea (GT) supplementation on body composition, blood lipids, blood glucose, and cardiovascular risk factors in overweight and obese females.MethodsThirty-nine healthy non-athlete overweight and obese females with an average age of 28.11 ± 6.50 years were sampled and randomly assigned to control (n = 13), AT (n = 13), and AT + GT (n = 13). Participants of the latter group received 33 mg of green tea after each main meal every day, and in addition, they were subjected to AT for eight weeks, including three 90-minute training sessions that were progressive, reaching 80% of the target heart rate (THR). Blood samples were taken from participants one week before the initiation of the study and 48 hours after the last training session.ResultsCompared to the control group, body weight, body fat percentage, body mass index (BMI), triglyceride, low-density lipoprotein, blood pressure, and heart rate (HR) significantly decreased in the groups treated with AT and AT + GT (P < 0.05). However, no significant changes occurred in FBS, HDL, TC, and WHR (P > 0.05).ConclusionsAT was effective in modifying cardiovascular risk factors, e.g. hypertension, heart rate (HR), triglyceride, and low-density lipoprotein (LDL). However, GT addition was not effective. Considering Iranians’ high tendency towards the consumption of plant materials, this finding needs further investigation.

The metabolic fate of dietary nicotine in the cabbage looper, Trichoplusia ni (Hübner)

Cabbage looper (Trichoplusia ni) larvae are generalist herbivores that feed on numerous cultivated plants and weeds including crucifers, other vegetables, flowers, and field crops. Consuming plant material from a wide range of plant species exposes these larvae to a considerable variety of plant secondary metabolites involved in chemical defense against herbivory. The ability of the cabbage looper larvae to detoxify plant secondary metabolites, such as nicotine, has been attributed to the rapid induction of excretion via the Malpighian tubules. However, the role of metabolism in the detoxification of plant secondary metabolites in cabbage looper larvae is not well studied. We investigated nicotine metabolism in 4th larval instar cabbage looper using UPLC-MS/MS analysis to resolve the time course of nicotine metabolism, the kinetic distribution of nicotine, and the presence or absence of major metabolites of nicotine in larval tissue and excretions. The major metabolite found in our analysis was cotinine, with trace amounts of cotinine N-oxide and nicotine N-oxide. The nicotine metabolites detected are similar to those of the nicotine-tolerant Lepidopteran tobacco hornworm (Manduca sexta). The results of our study demonstrate that the 5′C-oxidation of nicotine to cotinine is the primary pathway for nicotine metabolism in cabbage looper larvae. This study showed that metabolism of nicotine and subsequent excretion of nicotine and its metabolites occurs in the larvae of the cabbage looper. Our results suggest that 5′C-oxidation in lepidopteran insects is a conserved metabolic pathway for the detoxification of plant secondary metabolites.

Hormonally active phytochemicals and vertebrate evolution.

Living plants produce a diversity of chemicals that share structural and functional properties with vertebrate hormones. Wildlife species interact with these chemicals either through consumption of plant materials or aquatic exposure. Accumulating evidence shows that exposure to these hormonally active phytochemicals (HAPs) often has consequences for behavior, physiology, and fecundity. These fitness effects suggest there is potential for an evolutionary response by vertebrates to HAPs. Here, we explore the toxicological HAP–vertebrate relationship in an evolutionary framework and discuss the potential for vertebrates to adapt to or even co‐opt the effects of plant‐derived chemicals that influence fitness. We lay out several hypotheses about HAPs and provide a path forward to test whether plant‐derived chemicals influence vertebrate reproduction and evolution. Studies of phytochemicals with direct impacts on vertebrate reproduction provide an obvious and compelling system for studying evolutionary toxicology. Furthermore, an understanding of whether animal populations evolve in response to HAPs could provide insightful context for the study of rapid evolution and how animals cope with chemical agents in the environment.

Consumption of plant material by perch (Perca fluviatilis)

Abstract. While removing fish during reservoir biomanipulation, it was noted that the diet of normally piscivorous 5+ to 7+ perch was dominated by macrophyte fragments, with fish eggs sub-dominant. To the best of our knowledge, macrophytes have not previously been reported as a food item in perch. Here, we briefly discuss this finding and its significance for perch diet studies.

The effect of temperature on herbivory by the omnivorous ectotherm snail Lymnaea stagnalis

Rising temperatures likely affect the trophic interactions in temperate regions as global warming progresses. An open question is how a temperature rise may affect consumer pressure and plant abundance in shallow aquatic ecosystems, where most consumers are omnivorous. Interestingly, herbivory (plant-eating) is more prevalent toward low latitudes in ectotherms such as fish and aquatic invertebrates, and this may be temperature driven. We used pond snails (Lymnaea stagnalis L.) as a model aquatic ectotherm species and tested their consumption of both animal prey (Gammarus pulex L.) and plant material (Potamogeton lucens L.) at three different temperatures (15, 20, and 25°C). Higher temperatures led to higher consumption rates by the omnivore on both plant food and animal prey when fed separately. When the food was offered simultaneously, the pond snails consistently preferred animal prey over plant material at all tested temperatures. However, the omnivore did consume plant material even though they had enough animal prey available to them. Based on our experiments, we conclude that with increasing temperatures, L. stagnalis will only increase their consumption rates but not change food preference. Further studies are needed to test the generality of our findings across aquatic species to predict the effect of warming on aquatic plant consumption.