Morphology Of Mouthparts Research Articles

Morphology of the Mouthparts of Ladybeetle Vibidia duodecimguttata (Coleoptera: Coccinellidae), with Emphasis on Their Sensilla

Mouthparts are the feeding organs of insects, which play vital roles in the feeding process. The morphology of insect mouthparts has greatly evolved according to different foods and feeding habits. Therefore, studying the structure of the mouthparts is the key to understanding their feeding mechanisms. Vibidia duodecimguttata is an important biological control agent for powdery fungus. In this study, the fine morphology of the mouthpart of V. duodecimguttata was studied by scanning electron microscopy. The basic components of mouthpart of V. duodecimguttata are similar to those of other ladybeetles, while the specific morphology of each part is different. In total, six kinds of sensilla were identified on mouthpart, and twelve types of sensilla were divided according to their morphology, length and distribution. In addition, two kinds of glandular structures were also found, namely perforated plates and cuticular pores. Finally, the morphological differences between mycetophagous and other feeding habits ladybeetles were compared, and the function of each kind of sensilla was discussed, which may establish a solid foundation for further understanding of the feeding mechanism of ladybirds.

Functional morphology and ontogeny of mouthparts and mouth aperture of Panulirus ornatus and Sagmariasus verreauxi: Implications towards formulated feeds development

Development of formulated feed is now a focal point in advancing the aquaculture of spiny lobster species. This study investigated the functional morphology of two spiny lobsters, Panulirus ornatus and Sagmariasus verreauxi, by analysing mouthpart morphology and mouth aperture. The analysis is focussed on determining likely feed preference based on morphology with the aim to provide knowledge for the development of formulated feeds. There is a strong correlation between the mouth aperture being approximately 4.0 and 7.5% of the carapace length of S. verreauxi and P. ornatus juvenile and adult lobsters, respectively. This finding provides knowledge for development of a species-specific tool that could be used in experimental studies to define optimal dimensions of artificial manufactured pellets in relation to the size of the lobster. Differences in mouthpart morphology through ontogeny included increase of calcification and robustness, and this is likely to reflect a different requirement in the texture (softness/hardness) of the pellet as the animals develop. Spines and setation are a prominent feature of the mouthpart morphology and differ between species and during ontogeny. Spines on maxillipeds II and III and crista dentata on maxillipeds III are likely to play an important role in holding and manipulation of feed prior to ingestion. Pellet texture may need to accommodate these differences in species and age specific mouthpart ontogeny. Ontogenetic changes in setation were found, with much richer setation proportionally to the size of mouthpart in first instar juvenile lobsters, which decreases with size increase. Furthermore, species-specific differences indicate function shifts in mouthparts with life stages. This may indicate differences in filter feeding capacity with age and between species, as reported for other decapods. This is unlikely to be of high importance in pellet feeding but may represent an avenue of investigation for first feeds in juveniles. Collectively, the differences during ontogeny and between species suggest that formulated feeds may need to be tailored to species and life stage, particularly regarding pellet dimensions and texture.

The adaptive prowess of the lesser mealworm Alphitobius diaperinus (Coleoptera: Tenebrionidae): Insights from mouthpart morphology and mitogenomic analysis

The lesser mealworm, Alphitobius diaperinus (Panzer, 1797), is a pervasive pest known to infest stored products and poultry facilities worldwide, posing significant challenges for pest management. Understanding its adaptability to diverse environments is crucial for devising effective control strategies. This study investigated adult mouthparts and analyzed the mitogenome of A. diaperinus using specimens obtained from a cat litter box. The examination of mouthparts revealed notable intraspecific variations, suggesting potential adaptations to different ecological conditions. Analysis of the mitogenomes unveiled nucleotide variations in protein-coding genes (PCGs), ribosomal RNA genes (rRNAs), and the control region, with all mutations in PCGs being nonsynonymous, primarily occurring at the second codon positions. Evaluation of Ka/Ks ratios indicated purifying selection acting on the PCGs of A. diaperinus. Phylogenetic analyses consistently placed the newly sequenced sample within the same clade as previously sequenced A. diaperinus samples. The presence of A. diaperinus in cat litter highlights its remarkable adaptability to diverse habitats. Furthermore, intraspecific variation in mouthpart morphology and the mitogenome suggests ongoing adaptations to various food sources and environmental niches. These findings underscore the dynamic nature of A. diaperinus adaptations and emphasize the importance of continued research for effective pest management strategies.

Feeding selectivity and a functional trade-off in a benthic fish with a continuous morphological variation: an experimental test

BackgroundFunctional trade-offs through ecological specializations are hypothesized to become causes of adaptive phenotypic divergence under divergent natural selection, where intermediate phenotypes may have the lowest fitness. Evidence of phenotypic divergence in a trade-off between populations experiencing different environmental/ecological conditions is abundant. However, traits in divergent selection sometimes present non-discrete (unimodal) variability, including intermediate phenotypes, although the underlying mechanisms are poorly documented. A benthic cyprinid fish, Pseudogobio esocinus, in Lake Biwa, central Japan, exhibits a large non-discrete/continuous variation in mouthpart morphology (from wide to narrow) within a lake population. The variation is linked with individual diets (i.e., the compositions of two different types of prey) even at a single site, and thus the variability is hypothesized to persist under divergent selection for prey usage. As a first step toward understanding the persistence mechanisms, here I examined the presence of morphology-dependent feeding selectivity and a functional trade-off in a laboratory experiment.ResultsWhen each experimental fish was simultaneously provided the different types of prey (chironomid larvae and amphipods), the fish mostly utilized chironomid larvae as primary prey. However, compared with the wider-mouthed fish, the narrower-mouthed fish took a larger proportion of amphipods as secondary prey by changing feeding (attacking) behavior. The intermediate-mouthed fish had lower feeding efficiency than the extreme-mouthed fish, indicating potential disadvantage of the intermediate phenotype.ConclusionsThis experimental result supports the presence of morphology-dependent feeding performance and a functional trade-off with potential impacts on trait variability, which may favor specializations rather than generalizations. In the wild, however, there may be some situations for relaxing the trade-off, such as temporally fluctuating prey availability that could also favor generalizations depending on the conditions, and thus, both extreme and intermediate phenotypes may persist/coexist in a single habitat. Although further examinations, especially focusing on feeding efficiency for each prey type separated from the effects of prey selectivity, are needed, this case represents an opportunity to consider the possible mechanisms of the persistence of phenotypic variation that is maintained without divergence even in a trade-off.

A Study on the Feeding Biology of Soil Oribatid Mite Papillacarus (Papillacarus) elongatus (Acari, Lohmanniidae)

The feeding biology of lohmanniid mite Papillacarus (Papillacarus) elongatus Xavier, 2007 was investigated under laboratory conditions (relative humidity 80 ± 2 % and temperature 27 ± 2˚C) using appropriate feeding preference tests. Different microfungi and semi-degraded leaves were provided as food items. To validate feeding biology, the gut enzymes and structural morphology of mouth parts of P. (P.) elongatus were also examined. The results demonstrated that the P. (P.) elongatus are panphytophages, and could feed on both higher and lower plant elements. These alternative feeding guilds might enable these mites to coexist with other soil organisms; moreover, they can be directly involved in the biodegradation of leaf litter and indirectly influence the microbial activity in the soil ecosystem.

Mouthparts of the crab Goniopsis cruentata (Latreille, 1803) (Decapoda, Brachyura, Grapsidae): morphological variations associated with environment, sex and stage of development

Abstract Individuals and populations can display variations in distinct aspects of their life histories, which could be reflected in their morphological characteristics. This study analyzed the mouthpart morphology of the crab Goniopsis cruentata in relation to environment, sex and stage of development. Our results indicate differences in the number of setae between developmental stages and environments, as well as the interaction between developmental stages and environments. There were no differences in setae types between stages, sexes or environments. There were differences in the shape of the ischium between adults and juveniles, with a more homogeneous ischium in juveniles than adults. We also found differences in food content between developmental stages, as well as an interaction between developmental stages and environment. Our results support an association between diet and morphology of mouthparts in G. cruentata, and that these apparatuses vary according to ontogenetic development and the environmental conditions that species are exposed to. These associations should be considered in studies that use these characteristics to verify morphological responses to environmental variations.

Comparative morphology of the larval mouthparts among six species of Notodontidae (Insecta, Lepidoptera), with discussions on their feeding habits and pupation sites

Larval mouthparts are significant organs for the individual development, morphologically related with feeding habits, and providing valuable characters for taxonomy and phylogenetic analysis. In previous studies, larval mouthparts revealed two identifying characters of Notodontidae. However, the evolutionary driving force and exact definition of these structures remain unsatisfactory. In this study, the larval mouthparts of Euhampsonia cristata (Butler, 1877), Fentonia ocypete (Bremer, 1861), Phalera assimilis (Bremer & Grey, 1853), Nerice davidi Oberthür, 1881, Cerura erminea (Esper, 1783) and Furcula furcula (Clerck, 1759) are morphologically observed and compared using scanning electron microscopy (SEM). The larval mouthparts of the six species are commonly equipped with paired maxillary sacs, congruent with the previous descriptions. However, the larval mouthparts of N. davidi are peculiar for bearing toothed mandibles, providing an exception of Notodontidae. Otherwise, the mouthparts exhibit morphological differences on mandibles, spinnerets, labral notches, and setal arrangements among the six species. The morphological diversity and the related feeding and pupation habits are briefly discussed.

Philcarneum new genus and Constricticollis new genus, two distinctive rhinoceros beetles (Coleoptera: Scarabaeidae: Dynastinae: Pentodontini) from opposite sides of Australia with a revised key to the Australian dynastine genera

Females of two unusual dynastines (Coleoptera: Scarabaeidae: Dynastinae: Pentodontini) from Australia are described and compared with other known Australian genera and species. Philcarneum aenigma Allsopp & Hutchinson new genus, new species from coastal southeastern New South Wales was recognised as novel in the 1980s, but has lacked a formal name, making it ‘invisible’ in the literature. It is placed in the Cheiroplatina. Constricticollis clunis Hutchinson & Allsopp new genus, new species recently captured near Kununurra, northern Western Australia is placed in the Pentodontina. Within the Dynastinae many important generic-level characters relate to mouthpart morphology, which are not sexually dimorphic, thus allowing to determine females to genera in absence of males, whose secondary sexual characters (obvious horns, claw modifications, antennal club length, etc.) are often used in keys. The key to Australian Dynastinae in Weir et al. (2019) is modified to accommodate these two genera and Erbmahcedius Hutchinson & Allsopp, 2021. Distributional maps and data on habitats are provided.

Cavoperlidae, a new stonefly family (Insecta: Plecoptera) from mid-Cretaceous Kachin amber of northern Myanmar

A new genus and species of Plecoptera, Cavoperla excavata gen. et sp. nov., is described based on a male adult specimen preserved in mid-Cretaceous Kachin amber of northern Myanmar. This stonefly is assigned to the superfamily Pteronarcyoidea, which can be determined by its wing venation and mouthpart morphology. However, it exhibits a distinct set of characteristics that differentiate it from all known extant and extinct families within Pteronarcyoidea. To accommodate this unique taxon, a new extinct family, Cavoperlidae fam. nov., is established. Cavoperlidae fam. nov. shows a close relationship to the extant family Styloperlidae. Diagnostic features of Cavoperlidae fam. nov. include the presence of three well-developed ocelli, the absence of a male abdominal hair brush and the trifurcate setae on the apex of the tibia, and the unarmed basal cercal segments.

Comparative Material and Mechanical Properties among Cicada Mouthparts: Cuticle Enhanced with Inorganic Elements Facilitates Piercing through Woody Stems for Feeding

Adult cicadas pierce woody stems with their mouthparts to feed on xylem, suggesting the presence of cuticular adaptations that could increase hardness and elastic modulus. We tested the following hypotheses: (a) the mouthpart cuticle includes inorganic elements, which augment the mechanical properties; (b) these elements are abundant in specific mouthpart structures and regions responsible for piercing wood; (c) there are correlations among elements, which could provide insights into patterns of element colocalization. We used scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS) to investigate mouthpart morphology and quantify the elemental composition of the cuticle among four cicada species, including periodical cicadas (Magicicada sp.). Nanoindentation was used to quantify hardness and elastic modulus of the mandibles. We found 12 inorganic elements, including colocalized manganese and zinc in the distal regions of the mandible, the structure most responsible for piercing through wood; nanoindentation determined that these regions were also significantly harder and had higher elastic modulus than other regions. Manganese and zinc abundance relates to increased hardness and stiffness as in the cuticle of other invertebrates; however, this is one of the first reports of cuticular metals among insects with piercing-sucking mouthparts (>100,000 described species). The present investigation provides insight into the feeding mechanism of cicadas, an important but understudied component of their life traits.

Mouthpart Ecomorphology and Predatory Behaviour in Selected Rove Beetles of the "Staphylinine Group" (Coleoptera: Staphylinidae: Staphylininae, Paederinae).

Simple SummaryAn understanding of the evolution and diversity of organisms is vital not only in its own right, but also with regard to the way that ecosystems function and can be protected. We explore the mouthpart morphology, the feeding behaviour, and the predatory performance of several species within the hyperdiverse family of rove beetles (Staphylinidae, subfamilies Paederinae and Staphylininae) and the connections between these aspects by using scanning electron microscopy of dissected mouthparts and front legs and highspeed videography of prey-capture behaviour. Our behavioural and morphological findings indicate that the investigated representatives of the Paederinae are specialized on elusive prey such as springtails (Collembola), whereas the observed Staphylininae display characteristics more associated with generalist predation. The detected shape differences of the mandibles between the representatives of the two analysed subfamilies are correlated with predatory performance on specific types of prey. We also found correlations between body size and the preferred prey type. We describe several methods of prey capture: beetles use their front legs to attack their prey, to lift it off the ground, or to cage it. Such strategies differ among species and situations. Overall, this exploratory study provides valuable insights into the links between the morphology, behaviour, and predatory performance of rove beetles.The representatives of the megadiverse rove beetle subfamilies Paederinae and Staphylininae (Coleoptera: Staphylinidae) are considered generalist predators, although their exact prey-capture behaviour and performance and possible links to mouthpart morphology have rarely been described. Here, we examine these relationships for selected species by SEM analyses of mouthparts and front legs and highspeed videography of prey-capture behaviour. We describe the observed behaviours and structural properties and quantify relationships between prey type, mouthpart morphology, and predatory performance based on morphometric measurements of both the shape and lever properties of the mandible. We show that the Staphylininae considered have morphological and behavioural properties generally associated with generalist predation and that the Paederinae considered display characteristics that are highly specialized on elusive prey such as Collembola. We found correlations between mandible shape and leverage, and body size and prey type. We report distinct prey-capture behaviours: the beetles use front legs and/or mandibles to attack prey, drag prey, or cage it between their legs. These strategies differ among species and situations. Overall, this exploratory study provides insights into the morphology and types of prey capture that must have played a major role in the evolution of these beetles.

Morphological Description of Some Megachilidae Species in Aljabal Alakhder, Libya

Bees are a large and diverse species of insects belonging to the Hymenoptera order. The family Megachilidae represents a large part of most of the bee fauna all over the world as a result of their importance as pollinators. The study aimed to describe the morphological characteristics of three species of wild bees belonging to Megachile parientina (Geoffroy, 1785), Rhodanthidium sticticum (Fabricius, 1787), and Anthidium diadema Latreille, 1809 in Aljabal Alakder, Libya. Specimens were collected by hand net from different locations in the Aljabal Alakder area (Albayda and Alwastia). The morphological characters were described by using the OPTIC microscope. Measurements were taken at full body length (in cm), front wings length, thorax and abdomen width, body color was taken (head, abdomen, thorax, wings), and the study described in details the morphology of mouthparts, wings venation, antenna and abdominal structure for all species. The morphological structures vary between the different species in color, size, and wings. The body length of M. parientina was 19 mm, R. sticticum was 12 mm, and A. diadema was 13 mm. The study’s conclusion insists on the importance of morphological description studies to facilitate the identification of wild bees species in Libya.

Nematode contributions to the soil food web trophic structure of two contrasting boreal peatlands in Canada

Free-living soil nematodes span several trophic levels and play a key role in soil food webs. As such, the relative abundances and diversity of nematode feeding groups, along with nematode body size that is correlated with trophic transfer efficiency may provide useful information in understanding carbon and nitrogen cycling in soil systems. Yet, despite their role in soil carbon dynamics, there is a lack of knowledge regarding nematode trophic diversity in high carbon storage systems such as boreal peatlands. Here we assessed nematode communities using feeding groups (bacterivores, fungivores, herbivores, omnivores, and predators) based on mouthpart morphology, and their body sizes (length and mass) in two contrasting boreal peatlands in Northern Ontario, Canada that differ in vegetation (Sphagnum vs Carex), hydrology, nutrient availability, and microbial decomposition. We found that nematode trophic diversity was higher in the Sphagnum-dominated fen, and that the dominant nematode group corresponded to the dominant microbial group at each site. Predatory nematodes were significantly more abundant and larger in the Sphagnum-dominated fen, consistent with greater food web complexity, but the average body size of nematodes (all feeding groups included) was not significantly different between the fens. Taken together, these observed trends in nematode feeding groups and body sizes, along with higher microbial biomass in the Sphagnum-dominated fen supports the idea that the two sites may differ ecologically, and generally follow differences in microbial communities. Our study provides important baseline information for understanding peatland soil food web dynamics and their implications for carbon and nutrient dynamics.

Functional morphology of mouthparts and antennal sensillae of two co-generic aphidophagous ladybirds

Functional morphology of mouthparts and antennal sensillae of two co-generic aphidophagous ladybirds

Comparative morphology of the larval mouthparts among three Actias (Lepidoptera: Saturniidae), with descriptions on atypical spinnerets

Comparative morphology of the larval mouthparts among three Actias (Lepidoptera: Saturniidae), with descriptions on atypical spinnerets

Jigsaw dissection activity enhances student ability to relate morphology and ecology in aquatic insects

ABSTRACT Functional feeding guild classification of aquatic insects is partly based on mouthpart morphology, but the link between mouthpart morphology and ecological feeding roles is often missed by students in the classroom. We implemented a Jigsaw activity in a freshwater biology course to help students connect morphology and ecology. Paired students dissected two common (to the whole class) and one unique aquatic insect’s mouthparts and predicted their ecological feeding roles. Students then divided into new groups and taught peers about their unique insect. A pre- and post-activity survey measured students’ ability to relate morphology and feeding roles. Open-ended questions graded via a rubric showed students scored significantly higher and provided more answers discussing feeding roles. Likert-type questions probing students’ perceptions of mouthpart importance resulted in marginally higher importance ratings of mouthparts for identification but no differences for insect feeding. On an end-of-the-semester assessment, students generally rated the activity as helpful. Some reported the activity to be difficult due to small insect size. The activity enhanced students’ understanding of the link between mouthparts and feeding roles but may have decreased their engagement due to perceived difficulty. Further modification alleviating difficulty may improve student perceptions while retaining knowledge gains.

Tackling inconsistencies among freshwater invertebrate trait databases: harmonising across continents and aggregating taxonomic resolution

Abstract Use of invertebrate traits rather than species composition may facilitate large‐scale comparisons of community structure and responses to disturbance in freshwater ecology because the same traits potentially occur everywhere. In recent years, comprehensive invertebrate trait databases have been established at different scales (e.g., regions, continents). The wide availability of invertebrate trait data supports large‐scale studies. However, a number of data‐related issues complicate the use of invertebrate traits for ecological studies. It is uncertain how harmonising varying trait definitions among databases might influence subsequent identification of trait–environment relationships. Furthermore, there have been few comparisons of trait aggregation approaches with expert‐assigned trait affinities. We describe inconsistencies in the definitions of traits used to create freshwater invertebrate trait databases in Europe, North America, New Zealand, and Australia. Based on our comparisons of these databases, we established four novel trait datasets by harmonising definitions of commonly used traits. Next, we used two of these datasets to compare aggregated traits obtained by different aggregation methods with traits assigned by experts, both at the family level. The trait aggregation methods that we compared used either the mean or the median and different weightings. We further explored the effects of harmonisation and trait aggregation by re‐analysing data from a case study. We found that among databases, trait definitions often differed because varying numbers of traits were used to describe particular functions (e.g., respiration traits) and the way those functions were described also varied (e.g., for feeding mode some databases focused on the food source, whereas others focused on mouthpart morphology). The coding to describe traits (binary, fuzzy) also varied among databases. Our comparison of different aggregation methods showed that family‐level aggregated and expert‐assigned traits were similar, especially when traits were aggregated based on the median of trait values of taxa within a family. The case study showed that harmonised and aggregated data identified similar trait–environment relationships to non‐aggregated data. However, harmonised and aggregated data yielded only partially similar values for functional diversity metrics when compared to the case study results. By identifying inconsistencies in trait definitions we hope to motivate the development of standardised definitions for invertebrate traits. Our results also illustrate the usefulness of harmonised datasets for ecological study and provide guidance for the circumstances under which the choice of trait aggregation method is important.

The toolkit of a hunter – functional morphology of larval mouthparts in a dragonfly

AbstractThe diversity of mouthpart specializations in insects is staggering. As a direct consequence thereof, the knowledge about the mouthpart geometry, muscle attachment and feeding kinematics is incomplete for the vast majority of insect taxa – as it is for dragonflies. The adult dragonflies catch their prey in flight, while the aquatic larvae prey under water – both life stages being key predators in their biotopes. To gain insights into the functional morphology of the biting‐chewing mouthparts of larval Anax imperator, we combined results from micro computed tomography (µCT), confocal laser scanning microscopy (CLSM) and high‐speed videography. Anax imperator larvae were filmed during the feeding process to describe the movement and coordination of the mouthparts. These results, together with µCT‐data, allowing for a comprehensive visualization of the 3D‐geometry and corresponding musculature of each mouthpart. The material composition of the cuticle strongly influences the strength, mobility and durability of the cuticular components of the mouthparts. With this paper, we elucidate the anatomy, geometry and material composition of A. imperator's larval mouthparts in the light of the feeding process. Furthermore, we try to lay a foundation for functional morphological comparisons of mouthparts (1) between dragonfly species belonging to different eco‐types according to their food preferences and feeding habits or even (2) between different insect groups.

Evidence of a rapid and adaptive response of hemipteran mouthparts to a physical barrier.

Animals have encountered novel foods at points throughout history, due to factors such as range expansions and niche shifts driven by competition. One of the first challenges presented by novel foods is how to eat them. Mouthpart morphology is thus critical during the process of host shifts. Developmental plasticity in mouthparts is one potential mechanism that may allow animals to tolerate new foods and eventually to thrive upon them. Here, we investigated the extent to which insect mouthparts from two geographically distant populations can converge in morphology when feeding on common resources. We conducted a common garden/reciprocal transplant experiment using two populations of the cactus bug, Narnia femorata, that differ in mouthpart length. This insect uses straw-like mouthparts (hereafter 'beak') to get through the cactus fruit wall to reach the pulp inside. Our experimental results revealed clear developmental plasticity in beak length. Insects from both populations grew longer beaks when they fed on the cactus fruit with the thicker walls, and they grew shorter beaks when they fed on the cactus fruit with the thinner walls. Thus, insects from distant populations exhibited immediate developmental responses to a new food, and in the predicted directions. These results suggest that some fauna may be able to respond more rapidly than predicted when they encounter novel plants.

Morphology of adhesive surfaces in the sisorid catfish, Glyptothorax sinense sikkimensis

This paper deals with the surface morphology and structure of suctorial mouthparts, expanded paired fins and adhesive organ (AO) in a mountain stream catfish Glyptothorax sinense sikkimensis of India, as studied by scanning electron microscopy. It possesses type I taste buds on its barbels and lips. There are scattered unculiferous plaques on the lower lip and horny tubercles on outer fin rays, and knob like microstructures between fin rays of both paired fins. The thoracic region bears a prominent AO, which has 8-10unculiferous ridges arranged parallel to the body axis, separated by many non-unculiferous grooves. The latter may act as the major attachment sites and function as a suction cup. A combined action of the adhesive devices with their unique surface specializations enables the fish for better anchorage to sandy-rocky substratum of glacier-fed, rapid mountain streams. The plaques on lower lip and horny tubercles and knob like substructures in fin rays perhaps help in additional anchorage support to the major AO located at the thoracic area.