- Author: Kathy Keatley Garvey
In lekking, certain species of males in the animal world, including black grouse, peacock and owl parrots, congregate in a courtship ritual to entice females to mate with them. This is unusual because spiders are notoriously solitary and cannibalistic.
Two UC Davis spider experts played a key role in analyzing the genetics of this spider. The new species is an orb weaver named Isoxya manangona. Its species name is derived from the Malagasy verb meaning to "gather" or "aggregate."
Jason Bond, the Evert and Marion Schlinger Endowed Chair in the UC Davis Department of Entomology and Nematology and project scientist James Starrett headed the genetic analysis. The research paper was recently published in the journal, Insect Systematics and Diversity.
“This paper is significant in a number of respects including the discovery of a new species of orb web-weaving spider that is social; most spiders are solitary predators that are cannibalistic,” said Bond, who doubles as associate dean, UC Davis College of Agricultural and Environmental Sciences. “Although additional behavioral studies are needed to confirm, what is particularly interesting about this paper is that we report what is likely the first known observation of lekking behavior in spiders.”
Ingi Agnarsson, a professor of zoology at the University of Iceland and the Smithsonian Institution, Washington, D.C., headed the international team of researchers.
While looking for bark spiders in the rainforests of Andasibe-Mantadia National Park, the scientists observed large colonies of interconnected webs, built by what they later determined to be a new species.
In examining the webs, the researchers noticed multiple males gathering close together, sometimes touching, in a central, nonsticking line. They counted up to 41 interconnected, single-cohort adult female webs with up to 38 adult males aggregating on a central, single, nonsticky line.
In all, their mile-long research area yielded 22 spider colonies, ranging from 2 to 79 spiders in webs two inches to almost eight inches in size. The spiders are dark gray with black coloring and large protruding spines. The females are about 0.2 inches in size, with “cryptic yellow markings.” The males are smaller but with no yellow markings.
“Spiders are notoriously solitary and cannibalistic, with instances of colonial or social lifestyles in only about 50-60, or ~0.1% of 50,000 described species,” the authors wrote in their abstract. “Population analyses indicate that most colonies consist of multiple cohorts formed by close relatives. Territorial social spiders facultatively form colonies by interlinking individual webs, but further cooperation is infrequent, and only among juveniles or (rarely) females. In spiders therefore, aggregations of males outside of the male-male competition context has been unknown.”
The researchers noted that the males were “resting tightly together,” but they found “no evidence” of male-male aggression. “Genetic analyses from RAD sequencing suggest that most colonies consist of unrelated individuals,” they wrote in their abstract. “Furthermore, genetic variability of males was somewhat less than that of females. Single cohort colonies made up purely of adults, and peaceful male aggregations, have not previously been observed in spiders. Although direct behavioral observations are preliminary, we speculate based on the available evidence that these colonies may represent a novel and first case of lekking in spiders.”
Since it was near the end of the field season, the researchers had no opportunity for more observations, and never witnessed mating.
Other co-authors of the paper are Zachary Babbitz of Boston College, Matjaž Gregoric of the Slovenian Academy of Sciences and Arts, Onjaherizo Christian Raberahona of the University of Madagascar; Steven Williams, Oxford Brookes University, UK, and Matjaž Kuntner of the Smithsonian Institution.
Starrett, who joined the Bond lab in 2018, holds a doctorate in genetics, genomics and bioinformatics from UC Riverside. He is a former postdoctoral fellow (2016-2018) in the Jason Bond lab at Auburn University. Professor Bond joined the UC Davis faculty in 2018 from Auburn University, where he directed its Museum of Natural History (2011–2016), and served as professor and chair of the Auburn Department of Biological Sciences (2016–2018).
- Author: Kathy Keatley Garvey
And timely, too!
While many folks are panicking about the first detected (and destroyed) colony of Asian giant hornets, aka “murder hornets,” in North America, three entomologists have just published research on this and the 21 other known species of hornets in the genus Vespa, in the journal Insect Systematics and Diversity.
The article, “The Diversity of Hornets in the Genus Vespa (Hymenoptera: Vespidae; Vespinae); Their Importance and Interceptions in the United States,” is the work of three entomologists: lead author Allan Smith-Pardo, U.S. Department of Agriculture Animal and Plant Health Inspection Service (APHIS); and co-authors James Carpenter of the American Museum of Natural History's Division of Invertebrate Zoology, and Lynn Kimsey, director of the Bohart Museum of Entomology and professor of entomology at UC Davis.
North America's first known colony of the Asian giant hornet, Vespa mandarinia, was detected (and, yes, destroyed) in September 2019 on Vancouver Island, British Columbia. A single V. mandarinia was found dead in Blaine, Wash., in December 2019.
“Hornet species identification can be sometimes difficult because of the amount of intraspecific color and size variation,” the authors wrote in their abstract. “This has resulted in many species-level synonyms, scattered literature, and taxonomic keys only useful for local populations. We present a key to the world species, information on each species, as well as those intercepted at United States ports of entry during the last decade.”
Vespa species are “primarily predators of other insects, and some species are known to attack and feed on honey bees (Apis mellifera), which makes them a serious threat to apiculture,” the authors wrote in their abstract.
In the USDA-funded research, the trio combed through scientific literature and museum collections to separate the species. They list their sources and offer insights on the distribution of each hornet, and a discussion.
The Asian giant hornet's distribution is India, Sri Lanka, Bhutan, Nepal, Myanmar, Thailand, Laos, Vietnam, Malaysia, Malaya, China, Hong Kong, Taiwan, eastern Russia, Korea, Japan (including Ryukyus), the authors wrote.
The Bohart Museum of Entomology, home of a global collection of nearly eight million insect specimens, houses 20 specimens of V. mandarinia. The largest one, a queen, measures about an inch and a half long, Kimsey said.
“Insects introduced in the United States often come in cargo boxes from Asia to U.S. ports, establish colonies, and expand their range,” she said.
The only known European hornet to colonize the United States is Vespa crabro, introduced on the East Coast in the 1800s. “It is now fully established in the southeastern U.S,” Kimsey said. “A decade or more ago, there was a colony of another species, Vespa asiatica, reported near the Port of Long Beach but nothing ever came of that.”
What's next for the research team? "We will be continuing to create online identification tools and a detailed website," Kimsey said.
Research Conclusion:
"From 2010 to 2018, there have been close to 50 interceptions of Vespa (hornets) and Vespula (yellow jackets (Vespula) at U.S. ports of entry. Little less than half of those interceptions were hornets. The Vespa species intercepted include V. bellicosa, V. crabro, V. orientalis, V. mandarinia, and V. tropica. One of the interceptions of significance was an entire nest of V. mandarinia containing live brood and pupae that was sent via express courier from Asia. All species of Vespa, except V. crabro, which is already introduced into the eastern United States, are considered of quarantine importance by the USDA-APHIS."
A website, Invasive Hornets, part of a cooperation between the USDA, Animal Plant Health Inspection Service (APHIS), Plant Protection and Quarantine (PPQ) and the University of Georgia, is taking shape. According to the journal article: "This website contains more than 1,000 stacked, high-quality images of all the species and most of the races of the genus Vespa. It is important to have the resources for the identification and prevention of introduction of non-native species and to understand the potential effects of invasive hornets in our ecosystems. Hornets are dangerous for the beekeeping industry because they can alter pollination in agriculture and disrupt the beekeeping industry, as well as create public health and safety problem."
The authors credited senior museum scientists Christine Lebeau of the American Museum of Natural History and Steve Heydon of the Bohart Museum of Entomology “for helping to process the loan of Vespa material.” Mary Burns of the National Identification Services (NIS) of the USDA-APHIS- Plant Protection and Quarantine (PPQ) provided information about the number of interceptions of Vespa at U.S. ports of entry.
In an article posted in Entomology Today, science writer-educator Leslie Mertz wrote that the team is "building a publicly available, online adjunct to the newly published key that uses menus of distinguishing characteristics, as well as illustrations and photographs. They hope to have the online key up and running in 2021.”
- Author: Kathy Keatley Garvey
A year-long project on "Current Techniques in Morphology" was posted online today (Nov. 12).
Doctoral candidate Brendon Boudinot of the Phil Ward lab, UC Davis Department of Entomology and Nematology, edited the special collection of articles for the Entomological Society of America journal, Insect Systematics and Diversity (ISD). The work is publicized on EurekAlert! and the entire project can be accessed free online.
Boudinot co-led the development of the collection with István Mikó, collections manager at the University of New Hampshire Department of Biological Sciences.
For the year-long project. Boudinot and Mikó gathered articles illustrating cutting-edge research techniques in insect morphology and phylogenetics, including videos, interactive 3D images, and augmented reality.
"The increasing availability of advanced technologies, such as micro-computed tomography and confocal laser scanning microscopy, are allowing researchers to generate models of morphology in three and four dimensions based on physical data,” Boudinot wrote in the foreword. “These models not only allow for detailed and quantitative study of anatomical systems and their biomechanical properties, but they also allow end-users to experience the richness of morphology in virtual reality, which is incredible."
Boudinot marvels at the 3D models “which open new pathways of research and which you can manipulate on your computer, and another which can project your model in virtual reality on your phone or tablet.”
Boudinot also wrote an editorial on the future of morphology titled Toward Phylomics in Entomology: Current Systematic and Evolutionary Morphology.
Articles in the collection include:
- A Systematist's Guide to Estimating Bayesian Phylogenies From Morphological Data
- PARAMO: A Pipeline for Reconstructing Ancestral Anatomies Using Ontologies and Stochastic Mapping
- From Spinning Silk to Spreading Saliva: Mouthpart Remodeling in Manduca sexta (Lepidoptera: Sphingidae)
- Jumping and Grasping: Universal Locking Mechanisms in Insect Legs
- Revision of the Highly Specialized Ant Genus Discothyrea (Hymenoptera: Formicidae) in the Afrotropics with X-Ray Microtomography and 3D Cybertaxonomy
- Ready Species One: Exploring the Use of Augmented Reality to Enhance Systematic Biology with a Revision of Fijian Strumigenys (Hymenoptera: Formicidae)
“Morphology, encompassing the study of phenotypic form and function, is one of the ancient branches of human knowledge and is foundational for organismal classification,” Boudinot wrote in his editorial. “Two decades into the current century, the specialized biological knowledge of the history and pattern of evolution has been revolutionized by genome-scale sequencing technologies, and cryptic variation within and among species is quantifiable even with a few genetic markers. The application of statistical phylogenetic models of nucleotide and amino acid substitution to sequence data has enabled revised interpretations of morphological identities—be they population-level generalizations, such as species diagnoses, or the definition and homology of specific anatomical entities—and evolutionary transformation across the tree of life (e.g., insect genitalia, ancestral morphology of Polyneoptera). These models are also being adapted for phylogenetic analysis of morphological data, allowing explicit incorporation of fossil terminals and their stratigraphic information.”
Boudinot coined the word, “Phylomics,” which he said “can be defined as the inference of organismal evolution at the molecular and morphological scale, through the use of genomic and phenomic data (the ‘phenome' being a physical model of the phenotype of an organism, such as seen in the ISD special collection). The idea ultimately is to model the morphology of organisms across the phylogeny, through time, literally depicting ancestors and seeing the transformation from ancestor to descendant across the tree of life.”
UC Davis undergraduate student Ziv Lieberman of the Phil Ward lab (he's a senior majoring in evolution and ecology), and Francisco Hita-Garcia of Okinawa (of the Biodiversity and Biocomplexity Unit and Institute of Science and Technology Graduate University), served as the lead authors of “Revision of the Highly Specialized Ant Genus Discothyrea (Hymenoptera: Formicidae) in the Afrotropics with X-Ray Microtomography and 3D Cybertaxonomy.”
Lieberman and Hita-Garcia and three other co-authors described 15 new species in the genus, which is poorly represented in museum collections. Due to its “cryptic lifestyle, Discothyrea are poorly represented in museum collections and their taxonomy has been severely neglected,” they wrote. “We perform the first comprehensive revision of Discothyrea in the Afrotropical region through a combination of traditional and three-dimensional (3D) cybertaxonomy based on microtomography (micro-CT). Species diagnostics and morphological character evaluations are based on examinations of all physical specimens and virtual analyses of 3D surface models generated from micro-CT data.” These models can be seen for free in their article and online at https://sketchfab.com/arilab/collections/discothyrea.
Additionally, they applied “virtual dissections for detailed examinations of cephalic structures to establish terminology based on homology for the first time in Discothyrea. The complete datasets comprising micro-CT data, 3D surface models and videos, still images of volume renderings, and colored stacked images are available online as cybertype datasets (Hita Garcia et al. 2019, http://doi.org/10.5061/dryad.3qm4183).”
The journal, Insect Systematics and Diversity, launched by ESA in 2017, publishes research on systematics, evolution, and biodiversity of insects and related arthropods, including comparative and developmental morphology, conservation, behavior, taxonomy, molecular phylogenetics, paleobiology, natural history, and phylogeography.
The journal set out to host articles that utilize novel technologies or data types or describe emerging methods of research, ESA spokesperson Lisa Junker said. The new special collection on current techniques in morphology, she said, highlights how Insect Systematics and Diversity has become a premier outlet for integrative research combining multiple subdisciplines within the field.
