Brain size scaling through development in the whitelined sphinx moth (Hyles lineata) shows mass and cell number comparable to flies, bees, and wasps

Factors regulating larval growth and determinants of adult body size are described for several holometabolous insects, but less is known about brain size scaling through development. Here we use the isotropic fractionation ("brain soup") method to estimate the number of brain cells and cell density for the whitelined sphinx moth (Lepidoptera: Hyles lineata) from the first instar through the adult stage. We measure mass and brain cell number and find that, during the larval stages, body mass shows an exponential relationship with head width, while the total number of brain cells increases asymptotically. Larval brain cell number increases by a factor of ten from nearly 8000 in the first instar to over 80,000 in the fifth instar. Brain cell number increases by another factor of 10 during metamorphosis, with the adult brain containing more than 900,000 cells. This is similar to increases during development in the vinegar fly (Drosophila melanogaster) and the black soldier fly (Hermetia illucens). The adult brain falls slightly below the brain-to-body allometry for wasps and bees but is comparable in the number of cells per unit brain mass, indicating a general conservation of brain cell density across these divergent lineages.

Wettability and morphology of proboscises interweave with hawkmoth evolutionary history

Hovering hawkmoths expend significant energy while feeding, which should select for greater feeding efficiency. Although increased feeding efficiency has been implicitly assumed, it has never been assessed. We hypothesized that hawkmoths have proboscises specialized for gathering nectar passively. Using contact angle and capillary pressure to evaluate capillary action of the proboscis, we conducted a comparative analysis of wetting and absorption properties for 13 species of hawkmoths. We showed that all 13 species have a hydrophilic proboscis. In contradistinction, the proboscises of all other tested lepidopteran species have a wetting dichotomy with only the distal ∼10% hydrophilic. Longer proboscises are more wettable, suggesting that species of hawkmoths with long proboscises are more efficient at acquiring nectar by the proboscis surface than are species with shorter proboscises. All hawkmoth species also show strong capillary pressure, which, together with the feeding behaviors we observed, ensures that nectar will be delivered to the food canal efficiently. The patterns we found suggest that different subfamilies of hawkmoths use different feeding strategies. Our comparative approach reveals that hawkmoths are unique among Lepidoptera and highlights the importance of considering the physical characteristics of the proboscis to understand the evolution and diversification of hawkmoths.

Complete mitochondrial characteristics and phylogenetic analysis of Deilephila elpenor (Linnaeus, 1758) (Lepidoptera: Sphingidae)

Deilephila elpenor is widely distributed in countries of Asia and Central Europe, and the larva is recognized as significant agriculture pest. The complete mitochondrial genome of D. elpenor is 15,372 bp in length. It contains 13 protein-coding genes (PCGs), 22 tRNA genes, two rRNA genes, and a control region. TAA is utilized as the termination codon for most PCGs, however, cox1 and cox2 use the incomplete termination codon T, and nad3 uses TAG as the termination codon. UUA (Leu) is the most frequently used codon, GCG (Ala) and CCG (Pro) are the least frequently used codons. In addition, we selected 15 species sequences closest to this species from NCBI, and used Manduca quinquemaculata and Manduca sexta (Lepidoptera: Smerinthinae) as the outgroup. Phylogenetic analysis suggested that D. elpenor was the most closely related to genus Theretra, genus Rhagastis and Cechenena minor.

Haemolymph viscosity in hawkmoths and its implications for hovering flight

Viscosity determines the resistance of haemolymph flow through the insect body. For flying insects, viscosity is a major physiological parameter limiting flight performance by controlling the flow rate of fuel to the flight muscles, circulating nutrients and rapidly removing metabolic waste products. The more viscous the haemolymph, the greater the metabolic energy needed to pump it through confined spaces. By employing magnetic rotational spectroscopy with nickel nanorods, we showed that viscosity of haemolymph in resting hawkmoths (Sphingidae) depends on wing size non-monotonically. Viscosity increases for small hawkmoths with high wingbeat frequencies, reaches a maximum for middle-sized hawkmoths with moderate wingbeat frequencies, and decreases in large hawkmoths with slower wingbeat frequencies but greater lift. Accordingly, hawkmoths with small and large wings have viscosities approaching that of water, whereas hawkmoths with mid-sized wings have more than twofold greater viscosity. The metabolic demands of flight correlate with significant changes in circulatory strategies via modulation of haemolymph viscosity. Thus, the evolution of hovering flight would require fine-tuned viscosity adjustments to balance the need for the haemolymph to carry more fuel to the flight muscles while decreasing the viscous dissipation associated with its circulation.

Online citizen sciences reveal natural enemies and new occurrence data of Meteorusstellatus Fujie, Shimizu & Maeto, 2021 (Hymenoptera, Braconidae, Euphorinae)

Background

Citizen science is a research approach that involves collaboration between professional scientists and non-professional volunteers. The utilisation of recent online citizen-science platforms (e.g. social networking services) has greatly revolutionised the accessibility of biodiversity data by providing opportunities for connecting professional and citizen scientists worldwide. Meteorusstellatus Fujie, Shimizu & Maeto, 2021 (Hymenoptera, Braconidae, Euphorinae) has been recorded from the Oriental Islands of Japan and known to be a gregarious endoparasitoid of two macro-sized sphingid moths of Macroglossum, Ma.passalus (Drury) and Ma.pyrrhosticta Butler. It constructs characteristic star-shaped communal cocoons, suspended by a long cable. Although M.stellatus has been reported only from the Oriental Islands of Japan, the authors recognise its occurrence and ecological data from Taiwan and the Palaearctic Island of Japan through posts on online citizen-science groups about Taiwanese Insects on Facebook and an article on a Japanese citizen-scientist's website.

New information

Through collaboration between professional and citizen scientists via social media (Facebook groups) and websites, the following new biodiversity and ecological data associated with M.stellatus are provided: Meteorusstellatus is recorded for the first time from Taiwan and the Palaearctic Region (Yakushima Is., Japan).Cechetraminor (Butler, 1875), Hippotioncelerio (Linnaeus, 1758) and Macroglossumsitiene (Walker, 1856) (Lepidoptera, Sphingidae) are recorded for the first time as hosts of M.stellatus and two of which (C.minor and H.celerio) represent the first genus-level host records for M.stellatus.Mesochorus sp. (Hymenoptera, Ichneumonidae), indeterminate species of Pteromalidae and Trichogrammatidae (Hymenoptera), are recognised as hyperparasitoid wasps of M.stellatus.Parapolybiavaria (Fabricius, 1787) (Hymenoptera, Vespidae) is reported as a predator of pendulous communal cocoons of M.stellatus. The nature of suspended large-sized communal cocoons of M.stellatus and the importance and limitations of digital occurrence data and online citizen science are briefly discussed.

Contrasting Pollination Strategies and Breeding Systems in Two Native Useful Cacti from Southern Brazil

Brazil is one of the centers of diversity of Cactaceae, yet studies addressing both pollination biology and the breeding system in Brazilian cacti are scarce. We herein present a detailed analysis of two native species with economic relevance: Cereus hildmannianus and Pereskia aculeata. The first species produce edible, sweet, spineless fruits and the second species produces leaves with high protein content. Pollination studies were undertaken through fieldwork observations in three localities of Rio Grande do Sul, Brazil, over two flowering seasons, totaling over 130 observation hours. Breeding systems were elucidated utilizing controlled pollinations. Cereus hildmannianus is solely pollinated by nectar-gathering species of Sphingidae hawk moths. In contrast, the flowers of P. aculeata are pollinated by predominantly native Hymenoptera but also by Coleoptera and Diptera, which gather pollen and/or nectar. Both cacti species are pollinator-dependent; neither intact nor emasculated flowers turn into fruit, yet whereas C. hildmannianus is self-incompatible, P. aculeata is fully self-compatible. In sum, C. hildmannianus is more restrictive and specialized regarding its pollination and breeding system, whereas P. aculeata is more generalist. Understanding the pollination needs of these species is a necessary starting point towards their conservation but also for their proper management and eventual domestication.

Diversity of Lepidoptera (Insecta) recorded in a forest nursery of Nordeste County on São Miguel Island (Azores)

Background

The diversity of moth species (Insecta, Lepidoptera) recorded in the forest nursery of Nordeste County on São Miguel Island (Azores) is given. Adults were sampled between March and December 2019 using three methods: (i) light trap to catch Noctuidae species, (ii) open-sided delta trap baited with a synthetic female sex pheromone lure to attract Epiphyaspostvittana (Walker) males and (iii) entomological net to collect microlepidopteran moths. This contribution focuses mainly on the diversity of moths present in one forest nursery of Nordeste County of São Miguel Island (Azores), especially on the species associated with endemic and native plant species. It also contributes to better plan strategies for integrated protection and conservation measures, since nurseries host a great diversity of plants from the Laurel Forest, which may attract many lepidopteran species.

New information

A total of 10160 adults belonging to 33 lepidopteran species were recorded and listed by families, including: Argyresthiidae, one species (3%), Crambidae, four species (12%), Erebidae, one species (3%), Geometridae, five species (15%), Noctuidae, 18 species (55%), Sphingidae, one species (3%), Tineidae, one species (3%) and Tortricidae, two species (6%). The families Noctuidae, Geometridae and Crambidae were the most diverse. Those with the highest abundance of adults were the Noctuidae family, followed by the Geometridae, Crambidae, Tortricidae and Tineidae. The number of caught adults was consistently higher during spring and summer, decreasing sharply in late autumn. For 13 species caught in the light trap, the adult sex ratio was favourable to females. An analysis of the colonisation status, feeding and primary hosts of these endemic, native or exotic moth species contributes to our understanding of the factors that may lead to their establishment in Laurel Forest environments and to what extent there is a need to monitor and control them mainly with biological control agents.

Characterization of the Complete Mitochondrial Genome of Eight Diurnal Hawkmoths (Lepidoptera: Sphingidae): New Insights into the Origin and Evolution of Diurnalism in Sphingids

In this study, the mitochondrial genomes of 22 species from three subfamilies in the Sphingidae were sequenced, assembled, and annotated. Eight diurnal hawkmoths were included, of which six were newly sequenced (Hemaris radians, Macroglossum bombylans, M. fritzei, M. pyrrhosticta, Neogurelca himachala, and Sataspes xylocoparis) and two were previously published (Cephonodes hylas and Macroglossum stellatarum). The mitochondrial genomes of these eight diurnal hawkmoths were comparatively analyzed in terms of sequence length, nucleotide composition, relative synonymous codon usage, non-synonymous/synonymous substitution ratio, gene spacing, and repeat sequences. The mitogenomes of the eight species, ranging in length from 15,201 to 15,461 bp, encode the complete set of 37 genes usually found in animal mitogenomes. The base composition of the mitochondrial genomes showed A+T bias. The most commonly used codons were UUA (Leu), AUU (Ile), UUU (Phe), AUA (Met), and AAU (Asn), whereas GCG (Ala) and CCG (Pro) were rarely used. A phylogenetic tree of Sphingidae was constructed based on both maximum likelihood and Bayesian methods. We verified the monophyly of the four current subfamilies of Sphingidae, all of which had high support. In addition, we performed divergence time estimation and ancestral character reconstruction analyses. Diurnal behavior in hawkmoths originated 29.19 million years ago (Mya). It may have been influenced by the combination of herbaceous flourishing, which occurred 26-28 Mya, the uplift of the Tibetan Plateau, and the large-scale evolution of bats in the Oligocene to Pre-Miocene. Moreover, diurnalism in hawkmoths had multiple independent origins in Sphingidae.

A diversification relay race from Caribbean-Mesoamerica to the Andes: historical biogeography of Xylophanes hawkmoths

The regions of the Andes and Caribbean-Mesoamerica are both hypothesized to be the cradle for many Neotropical lineages, but few studies have fully investigated the dynamics and interactions between Neotropical bioregions. The New World hawkmoth genus Xylophanes is the most taxonomically diverse genus in the Sphingidae, with the highest endemism and richness in the Andes and Caribbean-Mesoamerica. We integrated phylogenomic and DNA barcode data and generated the first time-calibrated tree for this genus, covering 93.8% of the species diversity. We used event-based likelihood ancestral area estimation and biogeographic stochastic mapping to examine the speciation and dispersal dynamics of Xylophanes across bioregions. We also used trait-dependent diversification models to compare speciation and extinction rates of lineages associated with different bioregions. Our results indicate that Xylophanes originated in Caribbean-Mesoamerica in the Late Miocene, and immediately diverged into five major clades. The current species diversity and distribution of Xylophanes can be explained by two consecutive phases. In the first phase, the highest Xylophanes speciation and emigration rates occurred in the Caribbean-Mesoamerica, and the highest immigration rates occurred in the Andes, whereas in the second phase the highest immigration rates were found in Amazonia, and the Andes had the highest speciation and emigration rates.

Geographical and temporal distribution of hawkmoth (Lepidoptera: Sphingidae) species in Africa

Background

Hawkmoths consist of species where most adults are nocturnal, but there are some day-flying genera. Hawkmoth species have a wide variety of life-history traits, comprising species with adults (mostly nectarivorous though with some exceptions, honey-feeding), but there are also species that do not feed at all. The nectarivorous species are an important component of tropical ecosystems, with significant roles as major pollinators of both crops and wild flora with the pollination done by the adult stage. Pollinators are in decline world-wide and there is need for baseline data to provide information about their conservation strategies. Species occurrence data from Museum collections have been shown to be of great value as a tool for prioritising conservation actions in Africa. The National Museums of Kenya (NMK) have a large and active entomology collection that is in continuous growth. The NMK’s collection of hawkmoths had not been digitised prior to 2017. This moth family Sphingidae includes about 1,602 species and 205 genera worldwide (Kitching et al. 2018) with the majority of these species occurring in Africa. These moth species can also be used as indicators in biodiversity assessments as they can be easily sampled and identified. However, hawkmoths have rarely been surveyed over the long term for this purpose. Long-term datasets are of unquestionable significance for understanding and monitoring temporal changes in biodiversity. These hawkmoth data have addressed one of the most significant challenges to insect conservation, the lack of baseline information concerning species diversity and distribution and have provided key historic hawkmoth species diversity and distribution data that can be used to monitor their populations in the face of climate change and other environmental degradation issues that are facing the world today. The publication of the hawkmoth species occurrence data records in GBIF has enhanced data visibility to a wider audience promoting availability for use.

New information

The hawkmoth (Lepidoptera: Sphingidae) collection at the National Museums of Kenya was digitised from 2017 – 2020 and this paper presents details of species occurrence records as in the insect collection at the NMK, Nairobi, Kenya.

The collection holds 5,095 voucher specimens consisting of 88 genera and 208 species. The collection covers the period between 1904 and 2020.

The geographical distribution of the hawkmoths housed at the NMK covers East Africa at 81.41%, West Africa at 7.20%, Southern Africa at 6.89%, Central Africa at 4.02% and North Africa at 0.2%.

The Filippi's Glands of Giant Silk Moths: To Be or Not to Be?

Simple Summary

It is well documented that silkworms (Saturniidae) possess silk glands’ accessory glandular organs, the Filippi’s glands (FGs). These accessory glands are believed to play an important role in the cocoon construction. Unexpectedly, we have identified several silk moth species that are completely missing the FGs during the entire larval development and still produce fully functional cocoons. This finding suggests that the role of FGs is not crucial for the cocoon spinning.

Abstract

The Filippi’s glands (FGs), formerly “Lyonet’s glands”, are paired accessory organs associated with the silk glands. They are unique to Lepidoptera caterpillars and their exact role is not clear. The FGs are thought to be involved in the construction of a silk cocoon in bombycoid moths. FGs can differ in size and shape, therefore, in this study we attempt to find a correlation between FG morphology and phylogenetic position within the Bombycoidea. We use light and electron microscopy to examine the presence and morphology of FGs in a range of wild (giant) silk moths and several related species. Our results confirm that the majority of studied silk moth species have complex type of FGs that continuously increase in size during larval development. We identified several species of giant silk moths and two hawk moth species that completely lack FGs throughout their larval development. Finally, in several hawk moth species in which FGs are well developed during the first larval stage, these glands do not grow and remain small during later larval growth. Our results suggest that FGs are not critical for spinning and that loss of FGs occurred several times during the evolution of saturniids and sphingids. Comparison of FGs in different moths is an important first step in the elucidation of their physiological significance.

Intraspecific trait variability and community assembly in hawkmoths (Lepidoptera: Sphingidae) across an elevational gradient in the eastern Himalayas, India

We investigated some aspects of hawkmoth community assembly at 13 elevations along a 200- to 2770-m transect in the eastern Himalayas, a little studied biodiversity hot spot of global importance. We measured the morphological traits of body mass, wing loading, and wing aspect ratio of 3,301 free-ranging individuals of 76 species without having to collect or even constrain them. We used these trait measurements and T-statistic metrics to assess the strength of intracommunity ("internal") and extra-community ("external") filters which determine the composition of communities vis-a-vis the regional pool of species.The trait distribution of constituent species turned out to be nonrandom subsets of the community-trait distribution, providing strong evidence for internal filtering in all elevational communities. The external filter metric was more ambiguous. However, the elevational dependence of many metrics including that of the internal filter provided evidence for external (i.e., environmental) filtering. On average, a species occupied as much as 50%-75% of the total community-trait space, yet the T-statistic metric for internal filter was sufficiently sensitive to detect a strong nonrandom structure in the trait distribution.We suggest that the change in T-statistic metrics along the environmental gradient may provide more clues to the process of community assembly than previously envisaged. A large, smoothly varying and well-sampled environmental span would make it easier to discern them. Developing T-statistics for combined analysis of multiple traits will perhaps provide a more accurate picture of internal/filtering and niche complementarity. Moths are a hyperdiverse taxon and a very important component of many ecosystems. Our technique for accurately measuring body and wing dimensions of free-ranging moths can generate trait database for a large number of individuals in a time- and resource-efficient manner for a variety of community assembly studies using this important taxon.

Cryptic diversity in a vagile Hawaiian moth group suggests complex factors drive diversification

Allopatric speciation should be the dominant model of diversification across archipelagos because islands naturally promote isolation. It also follows that ecologically similar, vagile species should be more resistant to this kind of isolation due to dispersal and unifying selection. In a closely-related group of endemic Hawaiian hawkmoths, we found confounding patterns of inter-island connectivity and speciation that did not correlate with vagility, ecological specialization, or island age. Speciation occurred both in allopatric and sympatric taxa, with only the oldest and youngest islands fostering single-island endemic species. The intermediately-sized, central islands supported a combination of endemic and more widely-occurring lineages, suggesting no clear pattern leading to the current diversity in Hawaii. While some species are relatively common, others are apparently extinct or very rare, even on the same island. Further research into the specific mechanisms for these patterns in Hyles may prove broadly informative for understanding both cladogenesis and improving conservation planning. Our study identifies one new species endemic to Kauai and unique mitochondrial lineages in H. perkinsi, which may prove to be new species.

Fuelling on the wing: sensory ecology of hawkmoth foraging

Hawkmoths (Lepidoptera, Sphingidae) comprise around 1500 species, most of which forage on nectar from flowers in their adult stage, usually while hovering in front of the flower. The majority of species have a nocturnal lifestyle and are important nocturnal pollinators, but some species have turned to a diurnal lifestyle. Hawkmoths use visual and olfactory cues including CO₂ and humidity to detect and recognise rewarding flowers; they find the nectary in the flowers by means of mechanoreceptors on the proboscis and vision, evaluate it with gustatory receptors on the proboscis, and control their hovering flight position using antennal mechanoreception and vision. Here, we review what is presently known about the sensory organs and sensory-guided behaviour that control feeding behaviour of this fascinating pollinator taxon. We also suggest that more experiments on hawkmoth behaviour in natural settings are needed to fully appreciate their sensory capabilities.

Characterization of the complete mitochondrial DNA of Theretra japonica and its phylogenetic position within the Sphingidae (Lepidoptera, Sphingidae)

In the present study, the complete mitogenome of Theretra japonica was sequenced and compared with other sequenced mitogenomes of Sphingidae species. The mitogenome of T. japonica, containing 37 genes (13 protein-coding genes, 22 tRNA genes, and two rRNA genes) and a region rich in adenine and thymine (AT-rich region), is a circular molecule with 15,399 base pairs (bp) in length. The order and orientation of the genes in the mitogenome are similar to those of other sequenced mitogenomes of Sphingidae species. All 13 protein-coding genes (PCGs) are initiated by ATN codons except for the cytochrome C oxidase subunit 1 gene (cox1) which is initiated by the codon CGA as observed in other lepidopteran insects. Cytochrome C oxidase subunit 2 gene (cox2) has the incomplete termination codon T and NADH dehydrogenase subunit 1 gene (nad1) terminates with TAG while the remainder terminates with TAA. Additionally, the codon distributions of the 13 PCGs revealed that Ile and Leu2 are the most frequently used codon families and codons CGG, CGC, CCG, CAG, and AGG are absent. The 431 bp AT-rich region includes the motif ATAGA followed by a 23 bp poly-T stretch, short tandem repeats (STRs) of TC and TA, two copies of a 28 bp repeat 'ATTAAATTAATAAATTAA TATATTAATA' and a poly-A element. Phylogenetic analyses within Sphingidae confirmed that T. japonica belongs to the Macroglossinae and showed that the phylogenetic relationship of T. japonica is closer to Ampelophaga rubiginosa than Daphnis nerii. Phylogenetic analyses within Theretra demonstrate that T. japonica, T. jugurtha, T. suffusa, and T. capensis are clustered into one clade.

Functional characterization of the Hyles euphorbiae hawkmoth transcriptome reveals strong expression of phorbol ester detoxification and seasonal cold hardiness genes

Background

The European spurge hawkmoth, Hyles euphorbiae (Lepidoptera, Sphingidae), has been intensively studied as a model organism for insect chemical ecology, cold hardiness and evolution of species delineation. To understand species isolation mechanisms at a molecular level, this study aims at determining genetic factors underlying two adaptive ecological trait candidates, phorbol ester (TPA) detoxification and seasonal cold acclimation.

Method

A draft transcriptome of H. euphorbiae was generated using Illumina sequencing, providing the first genomic resource for the hawkmoth subfamily Macroglossinae. RNA expression levels in tissues of experimental TPA feeding larvae and cooled pupae was compared to levels in control larvae and pupae using 26 bp RNA sequence tag libraries (DeepSuperSAGE). Differential gene expression was assessed by homology searches of the tags in the transcriptome.

Results

In total, 389 and 605 differentially expressed transcripts for detoxification and cold hardiness, respectively, could be identified and annotated with proteins. The majority (22 of 28) of differentially expressed detox transcripts of the four 'drug metabolism' enzyme groups (cytochrome P450 (CYP), carboxylesterases (CES), glutathione S-transferases (GST) and lipases) are up-regulated. Triacylglycerol lipase was significantly over proportionally annotated among up-regulated detox transcripts. We record several up-regulated lipases, GSTe2, two CESs, CYP9A21, CYP6BD6 and CYP9A17 as candidate genes for further H. euphorbiae TPA detoxification analyses. Differential gene expression of the cold acclimation treatment is marked by metabolic depression with enriched Gene Ontology terms among down-regulated transcripts almost exclusively comprising metabolism, aerobic respiration and dissimilative functions. Down-regulated transcripts include energy expensive respiratory proteins like NADH dehydrogenase, cytochrome oxidase and ATP synthase. Gene expression patterns show shifts in carbohydrate metabolism towards cryoprotectant production. The Glycolysis enzymes, G1Pase, A1e, Gpi and an Akr isoform are up-regulated. Glycerol, an osmolyte which lowers the body liquid supercooling point, appears to be the predominant polyol cryoprotectant in H. euphorbiae diapause pupae. Several protein candidates involved in glucose, glycerol, myo-inositol and potentially sorbitol and trehalose synthesis were identified.

Conclusions

A majority of differently expressed transcripts unique for either detoxification or cold hardiness indicates highly specialized functional adaptation which may have evolved from general cell metabolism and stress response.The transcriptome and extracted candidate biomarkers provide a basis for further gene expression studies of physiological processes and adaptive traits in H. euphorbiae.

A global checklist of the Bombycoidea (Insecta: Lepidoptera)

Background

Bombycoidea is an ecologically diverse and speciose superfamily of Lepidoptera. The superfamily includes many model organisms, but the taxonomy and classification of the superfamily has remained largely in disarray. Here we present a global checklist of Bombycoidea. Following Zwick (2008) and Zwick et al. (2011), ten families are recognized: Anthelidae, Apatelodidae, Bombycidae, Brahmaeidae, Carthaeidae, Endromidae, Eupterotidae, Phiditiidae, Saturniidae and Sphingidae. The former families Lemoniidae and Mirinidae are included within Brahmaeidae and Endromidae respectively. The former bombycid subfamilies Oberthueriinae and Prismostictinae are also treated as synonyms of Endromidae, and the former bombycine subfamilies Apatelodinae and Phitditiinae are treated as families.

New information

This checklist represents the first effort to synthesize the current taxonomic treatment of the entire superfamily. It includes 12,159 names and references to their authors, and it accounts for the recent burst in species and subspecies descriptions within family Saturniidae (ca. 1,500 within the past 10 years) and to a lesser extent in Sphingidae (ca. 250 species over the same period). The changes to the higher classification of Saturniidae proposed by Nässig et al. (2015) are rejected as premature and unnecessary. The new tribes, subtribes and genera described by Cooper (2002) are here treated as junior synonyms. We also present a new higher classification of Sphingidae, based on Kawahara et al. (2009), Barber and Kawahara (2013) and a more recent phylogenomic study by Breinholt et al. (2017), as well as a reviewed genus and species level classification, as documented by Kitching (2018).

Mitochondrial genome of the sweet potato hornworm, Agrius convolvuli (Lepidoptera: Sphingidae), and comparison with other Lepidoptera species

In the present study, we sequenced the complete mitochondrial genome (mitogenome) of Agrius convolvuli (Lepidoptera: Sphingidae) and compared it with previously sequenced mitogenomes of lepidopteran species. The mitogenome was a circular molecule, 15 349 base pairs (bp) long, containing 37 genes. The order and orientation of genes in the A. convolvuli mitogenome were similar to those in sequenced mitogenomes of other lepidopterans. All 13 protein-coding genes (PCGs) were initiated by ATN codons, except for the cytochrome c oxidase subunit 1 (cox1) gene, which seemed to be initiated by the codon CGA, as observed in other lepidopterans. Three of the 13 PCGs had the incomplete termination codon T, while the remainder terminated with TAA. Additionally, the codon distributions of the 13 PCGs revealed that Asn, Ile, Leu2, Lys, Phe, and Tyr were the most frequently used codon families. All transfer RNAs were folded into the expected cloverleaf structure except for tRNA^Ser(AGN), which lacked a stable dihydrouridine arm. The length of the adenine (A) + thymine (T)-rich region was 331 bp. This region included the motif ATAGA followed by a 19-bp poly-T stretch and a microsatellite-like (TA)₈ element next to the motif ATTTA. Phylogenetic analyses (maximum likelihood and Bayesian methods) showed that A. convolvuli belongs to the family Sphingidae.

The long and the short of it: a global analysis of hawkmoth pollination niches and interaction networks

1. Proboscis length has been proposed as a key dimension of plant pollination niches, but this niche space has not previously been explored at regional and global scales for any pollination system. Hawkmoths are ideal organisms for exploring pollinator niches as they are important pollinators in most of the biodiverse regions of the earth and vary greatly in proboscis length, with some species having the longest proboscides of all insects. 2. Using datasets for nine biogeographical regions spanning the Old and New World, we ask whether it is possible to identify distinct hawkmoth pollination niches based on the frequency distribution of proboscis length, and whether these niches are reflected in the depths of flowers that are pollinated by hawkmoths. We also investigate the levels of specialization in hawkmoth pollination systems at the regional and community level using data from interaction network studies. 3. We found that most regional hawkmoth assemblages have bimodal or multimodal distributions of proboscis length, and that these are matched by similar distributions of floral tube lengths. Hawkmoths, particularly those with longer proboscides, are polyphagous and at the network level show foraging specialization equivalent to or less than that of bees and hummingbirds. In the case of plants, shorter-tubed flowers are usually visited by numerous hawkmoth species, while those that are longer-tubed tend to exclude shorter-proboscid hawkmoths and thus become ecologically specialized on longer-proboscid hawkmoth species. Longer-tubed flowers tend to have greater nectar rewards and this promotes short-term constancy by long-proboscid hawkmoths. 4. Our results show that pollinator proboscis length is a key niche axis for plants and can account for patterns of evolution in functional traits such as floral tube length and nectar volume. We also highlight a paradoxical trend for nectar resource niche breadth to increase according to proboscis length of pollinators, while pollinator niche breadth decreases according to the tube length of flowers.

Complete mitochondrial genome of the hawkmoth Notonagemia analis scribae (Lepidoptera: Sphingidae)

Currently, the mitochondrial genome of only two species of Sphingidae have been completely sequenced. For the phylogenetic study of Bombycoidea (including Bombycidae, Saturniidae and Sphingidae) using mitochondrial genomes (mitogenomes), more species are required as a basis for future research. In the present study, we sequenced the complete mitogenome of the hawkmoth, Notonagemia analis scribae (Lepidoptera: Sphingidae), to enrich the Sphingidae database. The length of the N. a. scribae genome was 15,303 bp with a typical set of genes (13 protein-coding genes [PCGs], 2 rRNA genes, and 22 tRNA genes), and one major non-coding A + T-rich region. The COI gene had a CGA start codon, which is the start codon for this gene in the majority of lepidopteran species, whereas other PCGs began with ATN codons. A 318-bp A + T-rich region harbored the blocks of conserved sequences that are typically found in lepidopteran insects, excluding a poly-A stretch, which is typically found at the end of the A + T-rich region. Phylogenetic analysis using the 13 PCGs indicated that N. a. scribae grouped together with two within-familial species, Sphinx morio and Manduca sexta, with the highest nodal support both by Bayesian inference and maximum-likelihood methods, forming the Sphingidae monophyletic group.

Single-Component Pheromone Consisting of Bombykal in a Diurnal Hawk Moth, Neogurelca himachala sangaica

Recent work has suggested that hawk moths share pheromone components but are sexually separated by qualitative and quantitative differences in their pheromone blends. During field assays on the sex pheromones of other species, a diurnal hawk moth, Neogurelca himachala sangaica (Lepidoptera: Sphingidae), was frequently captured, but the composition of the sex pheromone of this species was not known. Analysis of hexane extracts of the pheromone glands of calling female by gas chromatography (GC) using an electroantennographic detector (EAD) revealed two components that elicited EAD responses from male moth antennae. These components were identified by their mass spectra and retention indices on two GC columns as (10E,12Z)-10,12-hexadecadienal (E10,Z12-16:Ald) and a trace of its (10E,12E)-isomer (E10,E12-16:Ald) in 98:2 ratio. In field experiments, E10,Z12-16:Ald alone attracted male moths, and addition of E10,E12-16:Ald significantly reduced the attractiveness, even at the naturally-occurring ratio. Analysis of the data using a generalized linear mixed model showed that E10,Z12-16:Ald positively contributed to attractiveness, whereas E10,E12-16:Ald did so negatively, and it was concluded that the sex pheromone of N. himachala sangaica consists solely of E10,Z12-16:Ald, bombykal. The negative effect of E10,E12-16:Ald on attractiveness could promote the species-specificity of this single-component pheromone system.

Night life on the beach: selfing to avoid pollinator competition between two sympatric Silene species

BACKGROUND AND AIMS

Evolution of autonomous selfing may be advantageous because it allows for reproductive assurance. In co-flowering plants competing for pollinators, the least common and/or attractive could suffer pollen limitations. Silene niceensis and S. ramosissima are taxonomically related species sharing the same habitat, although S. ramosissima is less abundant and has a more restricted distribution. They also have the same a priori nocturnal pollinator syndrome, and show an overlapping flowering phenology. The aim of this study was to investigate whether a selfing strategy in S. ramosissima allows it to avoid pollinator competition and/or interspecific pollen transfer with S. niceensis, which would thus enable both species to reach high levels of fruit and seed set.

METHODS

The breeding system, petal colour, flower life span and degree of overlap between male and female phases, floral visitor abundance and visitation rates were analysed in two sympatric populations of S. niceensis and S. ramosissima in southern Spain.

KEY RESULTS

Autonomous selfing in S. ramosissima produced very high fruit and seed set, which was also similar to open-pollinated plants. Silene niceensis showed minimum levels of autonomous selfing, and pollen/ovule ratios were within the range expected for the breeding system. In contrast to S. niceensis, flower life span was much shorter in S. ramosissima, and male and female organs completely overlapped in space and time. Upper surface petals of both species showed differing brightness, chroma and hue. Flowers of S. niceensis were actively visited by moths, hawkmoths and syrphids, whereas those of S. ramosissima were almost never visited.

CONCLUSIONS

The findings show that different breeding strategies exist between the sympatric co-flowering S. niceensis and S. ramosissima, the former specializing in crepuscular-nocturnal pollination and the latter mainly based on autonomous selfing. These two strategies allow both species to share the restricted dune habitat in which they exist, with a high female reproductive success due to the absence of pollinator competition and/or interspecific pollen flow.

Importance of Habitat Heterogeneity in Richness and Diversity of Moths (Lepidoptera) in Brazilian Savanna

Moths exhibit different levels of fidelity to habitat, and some taxa are considered as bioindicators for conservation because they respond to habitat quality, environmental change, and vegetation types. In this study, we verified the effect of two phytophysiognomies of the Cerrado, savanna and forest, on the diversity distribution of moths of Erebidae (Arctiinae), Saturniidae, and Sphingidae families by using a hierarchical additive partitioning analysis. This analysis was based on two metrics: species richness and Shannon diversity index. The following questions were addressed: 1) Does the beta diversity of moths between phytophysiognomies add more species to the regional diversity than the beta diversity between sampling units and between sites? 2) Does the distribution of moth diversity differ among taxa? Alpha and beta diversities were compared with null models. The additive partitioning of species richness for the set of three Lepidoptera families identified beta diversity between phytophysiognomies as the component that contributed most to regional diversity, whereas the Shannon index identified alpha diversity as the major contributor. According to both species richness and the Shannon index, beta diversity between phytophysiognomies was significantly higher than expected by chance. Therefore, phytophysiognomies are the most important component in determining the richness and composition of the community. Additive partitioning also indicated that individual families of moths respond differently to the effect of habitat heterogeneity. The integrity of the Cerrado mosaic of phytophysiognomies plays a crucial role in maintaining moth biodiversity in the region.

Tempo and mode of antibat ultrasound production and sonar jamming in the diverse hawkmoth radiation

The bat-moth arms race has existed for over 60 million y, with moths evolving ultrasonically sensitive ears and ultrasound-producing organs to combat bat predation. The evolution of these defenses has never been thoroughly examined because of limitations in simultaneously conducting behavioral and phylogenetic analyses across an entire group. Hawkmoths include >1,500 species worldwide, some of which produce ultrasound using genital stridulatory structures. However, the function and evolution of this behavior remain largely unknown. We built a comprehensive behavioral dataset of hawkmoth hearing and ultrasonic reply to sonar attack using high-throughput field assays. Nearly half of the species tested (57 of 124 species) produced ultrasound to tactile stimulation or playback of bat echolocation attack. To test the function of ultrasound, we pitted big brown bats (Eptesicus fuscus) against hawkmoths over multiple nights and show that hawkmoths jam bat sonar. Ultrasound production was immediately and consistently effective at thwarting attack and bats regularly performed catching behavior without capturing moths. We also constructed a fossil-calibrated, multigene phylogeny to study the evolutionary history and divergence times of these antibat strategies across the entire family. We show that ultrasound production arose in multiple groups, starting in the late Oligocene (∼ 26 Ma) after the emergence of insectivorous bats. Sonar jamming and bat-detecting ears arose twice, independently, in the Miocene (18-14 Ma) either from earless hawkmoths that produced ultrasound in response to physical contact only, or from species that did not respond to touch or bat echolocation attack.

Hawkmoths produce anti-bat ultrasound

Bats and moths have been engaged in aerial warfare for nearly 65 Myr. This arms race has produced a suite of counter-adaptations in moths, including bat-detecting ears. One set of defensive strategies involves the active production of sound; tiger moths' ultrasonic replies to bat attack have been shown to startle bats, warn the predators of bad taste and jam their biosonar. Here, we report that hawkmoths in the Choerocampina produce entirely ultrasonic sounds in response to tactile stimulation and the playback of biosonar attack sequences. Males do so by grating modified scraper scales on the outer surface of the genital valves against the inner margin of the last abdominal tergum. Preliminary data indicate that females also produce ultrasound to touch and playback of echolocation attack, but they do so with an entirely different mechanism. The anti-bat function of these sounds is unknown but might include startling, cross-family acoustic mimicry, warning of unprofitability or physical defence and/or jamming of echolocation. Hawkmoths present a novel and tractable system to study both the function and evolution of anti-bat defences.

Dietary plant phenolic improves survival of bacterial infection in Manduca sexta caterpillars

Plant phenolics are generally thought to play significant roles in plant defense against herbivores and pathogens. Many plant taxa, including Solanaceae, are rich in phenolic compounds and some insect herbivores have been shown to acquire phenolics from their hosts to use them as protection against their natural enemies. Here we demonstrate that larvae of an insect specialist on Solanaceae, the tobacco hornworm, Manduca sexta L. (Lepidoptera: Sphingidae), acquire the plant phenolic chlorogenic acid (CA), and other caffeic acid derivatives as they feed on one of their hosts, Nicotiana attenuata L. (Solanaceae), and on artificial diet supplemented with CA. We test the hypothesis that larvae fed on CA-supplemented diet would have better resistance against bacterial infection than larvae fed on a standard CA-free diet by injecting bacteria into the hemocoel of fourth instars. Larvae fed CA-supplemented diet show significantly higher survival of infection with Enterococcus faecalis (Andrewes & Horder) Schleifer & Kilpper-Bälz, but not of infection with the more virulent Pseudomonas aeruginosa (Schroeter) Migula. Larvae fed on CA-supplemented diet possess a constitutively higher number of circulating hemocytes than larvae fed on the standard diet, but we found no other evidence of increased immune system activity, nor were larvae fed on CA-supplemented diet better able to suppress bacterial proliferation early in the infection. Thus, our data suggest an additional defensive function of CA to the direct toxic inhibition of pathogen proliferation in the gut.