Do you know your spiders?

If you engage in social media, you've probably seen a "what-is-this" query about a spider that some unsuspecting person discovered quite unexpectedly in a garden, bedroom, bathroom or garage. Triple exclamation points usually accompany "Yecch!!!" (Expletives usually require quadruple exclamation points.)

For a good general view of spiders, check out the UC Statewide Integrated Pest Management Program's newly revised "Spiders" Pest Note. 

"Many people fear or dislike spiders," according to the site, but "for the most part, spiders are beneficial because of their role as predators of insects and other arthropods, and most cannot harm people. Spiders that might injure people—for example, black widows—generally spend most of their time hidden outside homes in woodpiles or in clutter in the garage. The spiders commonly seen out in the open during the day are unlikely to bite people."

Spiders, which are arachnids, differ from insects in that they have eight legs (not six) and have no wings or antennae. 

UC IPM offers information on black widow spiders, yellow sac spiders and recluse spiders (which, contrary to popular opinion, are NOT found in California). The website also touches on jumping spiders, hobo spiders, common house spiders, and tarantulas. A table, illustrated with photos, lists the common spider families in North America, including:

• Agelenidae, funnel weavers or grass spiders
• Araneidae, orb weavers or garden spiders
• Clubionidae (including Corinnidae), sac spiders or twoclawed hunting spiders
• Linyphiidae (=Microphantidae), dwarf spiders
• Lycosidae, wolf spiders
• Oxyopidae, lynx spiders
• Salticidae, jumping spiders
• Theridiidae, cobweb, cobweb weaver, or combfooted spiders
• Thomisidae, crab spiders or flower spiders

What about spider bites? "Unlike mosquitoes, spiders do not seek people in order to bite them," UC IPM says, tongue in cheek. "Generally, a spider doesn't try to bite a person unless it has been squeezed, lain on, or similarly provoked to defend itself. Moreover, the jaws of most spiders are so small that the fangs cannot penetrate the skin of an adult person. Sometimes when a spider is disturbed in its web, it may bite instinctively because it mistakenly senses that an insect has been caught."

If you've got a hankering to see a live tarantula (who doesn't?), you can do so when the Bohart Museum of Entomology at UC Davis opens its doors again to the public. The Bohart Museum, home of nearly eight million insect specimens, a gift shop (now online), and a live "petting zoo" (think Madagascar hissing cockroaches, walking sticks and taranatulas) is located in Room 1124 of the Academic Surge Building on Crocker Lane. UC Davis spider expert Professor Jason Bond and his lab usually present a program there at least once a year or engage with folks at the open houses. Bond serves as the Evert and Marion Schlinger Endowed Chair in Insect Systematics, UC Davis Department of Entomology and Nematology. (See his lab website) 

As an aside, Professor Bond "bonds" with spiders. Yes, he does. And he's never met a spider he didn't like.  

Chances are you're not thinking about spiders right now, but arachnid experts at the University of California, Davis, are.

Two doctoral students from the Jason Bond laboratory, UC Davis Department of Entomology and Nematology, won first- and second-place awards in the student research competitions at the recent meeting of the American Arachnological Society, held at Washington and Lee University, Lexington, Va.

Rebecca Godwin won first in the poster competition for her research on trapdoor spiders and Lacie Newton won second for her oral presentation on species delimitation.

Congratulations to these dedicated doctoral students!

Godwin titled her work, “Revision of New World Ummidia (Mygalomorphae, Halonoproctidae)”: Her abstract: “Ummidia is a historically taxonomically difficult group of spiders belonging to the infraorder Mygalomorphae, one of the three main lineages recognized within spiders. Mygalomorph life history and their incredibly cryptic appearance make them difficult to identify, as a result they are frequently overlooked by spider systematists. Ummidia Thorell 1875 is a wide-ranging genus of trapdoor spider found both in the Mediterranean region of the Old World and in the New World from the eastern United States south to Brazil. Taxonomic work on New World Ummidia is sparse outside of original descriptions, the most recent of which are over half a century old."

"I am revising the genus Ummidia in the Nearctic region. I have approached this taxonomic problem by examining approximately 700 specimens of Ummidia from various collections (American Museum of Natural History, Museum of Comparative Zoology, Florida State Collection of Arthropods, California Academy of Sciences, and Auburn University Museum of Natural History). Examination of museum material has seemingly confirmed the undescribed diversity of Ummidia; preliminary estimates of New World species ranging between 50 and 60, with particularly high amounts of diversity in the Florida and Virginia. This study, along with many others conducted utilizing museum collections, is indicative of the importance of natural history collections and their usefulness in discovering unknown biodiversity.”

Lacie titled her work, “Species Delimitation of the Antrodiaetus Unicolor Species Complex Using a 3RAD Approach.” Her abstract: “Although species delimitation can be highly contentious, the development of reliable methods to accurately ascertain species boundaries is a fundamental and necessary step in cataloguing and describing Earth's quickly disappearing biodiversity. Species delimitation in spider taxa has historically been based on morphological characters; however, certain mygalomorphs are morphologically indistinguishable from each other yet have considerable molecular divergence."

"Previous research by Hendrixson and Bond (2005) described a new sympatric species Antrodiaetus microunicolor in the A. unicolor species complex using morphological criteria (i.e. size and setal character differences) and behavioral criteria (non-overlapping mating seasons). Subsequently, they used two molecular markers COI and 28S and discovered that A. unicolor is paraphyletic with respect to A. microunicolor. To further delineate this species complex, we implement the cohesion species concept and employ multiple lines of evidence for testing genetic exchangeability and ecological interchangeability. Our integrative approach includes extensively sampling homologous loci across the genome using a version of RADseq called 3RAD, assessing population structure across their geographic range, and evaluating ecological similarity by niche-based distribution modeling. Based on our analyses, we conclude that this species complex has two or three species in addition to A. microunicolor.”

Rebecca Godwin
Godwin holds two degrees from Auburn University: her bachelor's degree in zoology in 2004, and her master's degree in wetland biology in 2011. She began her doctoral studies at Auburn University in 2014, and transferred to UC Davis when Bond accepted the UC Davis position in 2018.

Godwin won the Auburn University's Department of Biological Science's Outstanding Service Award in 2016. She is the lead author of research published in 2018 in the journal Molecular Phylogenetics and Evolution on “Phylogeny of a Cosmopolitan Family of Morphologically Conserved Trapdoor spiders (Mygalomorphae, Ctenizidae) Using Anchored Hybrid Enrichment, with a Description of the Family, Halonoproctidae Pocock 1901.” She currently serves as a graduate teaching assistant in the course, "Biology 2C," at UC Davis.

Godwin's research interests include taxonomy, systematics, and phylogreography of trapdoor spiders, as well as effective science communication and increasing general science literacy.

Lacie Newton
Newton received her bachelor of science degree from Millsaps College, Jackson, Miss., in 2016, and then joined the Auburn University doctoral program. Like Godwin, she transferred to UC Davis with her major professor in 2018. Newton served as an undergraduate teaching assistant at Millsaps College for “Introduction to Cell Biology” and “General Zoology,” and as a graduate teaching assistant in “Introduction to Biology” at Auburn University.

Newton now serves as a graduate teaching assistant at UC Davis for “Introduction to Biology: Biodiversity and the Tree of Life.” She won the 2019-2020 George H. Vansell Scholarship, UC Davis. Her research interests include systematics, species delimitation, and phylogeography of spiders; phylogenetics; comparative transcriptomics of troglophilic and troglobitic spiders; cave biology and conservation.

Both Godwin and Newton volunteer at the Bohart Museum of Entomology's programs on spiders and at the campuswide UC Davis Biodiversity Museum Day.

Bond joined the UC Davis faculty after a seven-year academic career at Auburn University, Ala. He served as professor of biology and chair of the Department of Biological Sciences from January 2016 to July 2018, and as curator of arachnids and myriapods (centipedes, millipedes, and related animals) at the Auburn University Museum of Natural History, from August 2011 to July 2018. 

What's for dinner?

A crab spider, camouflaged in our lavender patch, didn't catch a honey bee, a butterfly, an ant or a syrphid fly.

No, it nailed a green bottle fly.

We couldn't help but notice. The fly's metallic blue-green coloring stood in sharp contrast to the white spider.

One venomous bite to kill it. And soon the fly, Lucilia sericata, was toast. Milk toast.

Crab spiders don't build webs to trap their prey. They're cunning and agile hunters that spring into action when an unsuspecting prey appears on the scene. They belong to the family Thomisidae, which includes some 175 genera and more than 2100 species. And they're ancient: spiders date back 400 million years ago.

Do you like spiders? You should.

“Spiders are an incredibly diverse group with more than 50,000 species described with probably another 200,000 remaining to yet be discovered,” says spider expert Jason Bond, the Evert and Marion Schlinger Endowed Chair in Insect Systematics in the UC Davis Department of Entomology and Nematology.

It's worth repeating what Professor Bond said about spiders at the Bohart Museum of Entomology open house, “Eight-Legged Wonders,” on Saturday, March 9.

The five good reasons to like spiders:

1. Spiders consume 400-800 million tons of prey, mostly insects, each year. Humans consume somewhere around 400 million tons of meat and fish each year.
2. Spider silk is one of the strongest naturally occurring materials. Spider silk is stronger than steel, stronger and more stretchy than Kevlar; a pencil thick strand of spider silk could be used to stop a Boeing 747 in flight.
3. Some spiders are incredibly fast – able to run up to 70 body lengths per second (10X faster than Usain Bolt).
4. Athough nearly all 47,000-plus spider species have venom used to kill their insect prey, very few actually have venom that is harmful to humans.
5. Some spiders are really good parents –wolf spider moms carry their young on their backs until they are ready to strike out on their own; female trapdoor spiders keep their broods safe inside their burrows often longer than one year, and some female jumping spiders even nurse their spiderlings with a protein rich substance comparable to milk.

Size does matter.

Have you ever wondered about sexual size dimorphism in the tropical spiders, the golden orbweavers?

The females are sometimes 10 times larger and 100 times heavier than their male counterparts. And the webs that the females  weave are huge--they can be as wide as five feet in diameter.

And, yes, the females cannibalize the males, says Jason Bond, professor and Schlinger Chair in Insect Systematics, UC Davis Department of Entomology and Nematology, 

“Sexual size dimorphism (SSD) often seems to be correlated with extreme morphological, behavioral and life history phenotypes in either sex,” says Bond,   senior author of a newly published paper in the Journal of Systematic Biology, a peer-reviewed scientific journal published by Oxford University Press on behalf of the Society of Systematic Biologists.

Through phylogenomic (the intersection of the fields of evolution and genomics) and comparative analyses, Bond and his colleagues found that golden orbweavers “ignore biological rules.”

The global team of 11 scientists--from Slovenia, China, Taiwan, Czech Republic and the United States (UC Davis, Smithsonian Institution, University of Idaho, University of Florida and University of Vermont)--unraveled a complex evolution of sexual size and dimorphism and found that Nephilid female gigantism is a “phylogenetically ancient phenotype, over 100 million years old, though their magnitudes vary by lineage.”

The spiders belong to the genus Nephila and family Nephilidae; the members are known for constructing huge or exaggerated webs. The species thrive in warmer regions throughout the world, including Australia, Asia, Africa (including Madagascar) and the America. One species, N. clavipes, is found in southern United States, from Texas to North Carolina.

For the paper, “Golden Orbweavers Ignore Biological Rules: Phylogenomic and Comparative Analyses Unravel a Complex Evolution of Sexual Size Dimorphism,” the team tested two biological rules: Cope's rule and Rensch's rule. Cope's rule postulates that population lineages tend to increase in body size over evolutionary time. Rensch's rule is a biological rule on allometric patterns of male and female size. Neither rule applied to the golden orbweavers.

First, the scientists established the backbone phylogeny of Nephilidae, using 367 anchored hybrid enrichment markers, and then combined these data with classical markers for a reference species level phylogeny.

“Second, we used the phylogeny to test Cope and Rensch's rules, sex specific size optima, and the coevolution of web size, type, and features with female and male body size and their ratio, SSD,” they wrote in their abstract. “Male, but not female, size increases significantly over time, and refutes Cope's rule. Allometric analyses reject the converse, Rensch's rule. Male and female body sizes are uncorrelated. Female size evolution is random, but males evolve toward an optimum size (3.2–4.9 mm). Overall, female body size correlates positively with absolute web size. However, intermediate-sized females build the largest webs (of the hybrid type), giant female Nephila and Trichonephila build smaller webs (of the aerial type), and the smallest females build the smallest webs (of the arboricolous type).”

In conclusion, the scientists proposed a new clade, a group of organisms evolving from a common ancestor. They resurrected the family Nephilidae and proposed the new clade, Orbipurae, to contain Araneidae Clerck 1757, Phonognathidae Simon 1894, new rank, and Nephilidae.

The researchers proposed “taxonomic changes based on the criteria of clade age, monophyly and exclusivity, classification information content, and diagnosability. Spider families, as currently defined, tend to be between 37 million years old and 98 million years old, and Nephilidae is estimated at 133 million years old, thus deserving family status.”

“Nephilid female gigantism is a phylogenetically ancient phenotype (over 100 million years old), as is extreme sexual size dimorphism, though their magnitudes vary by lineage,” they wrote. “Despite the sometimes conflicting trends seen within Nephilidae, the clade stands as the most extreme example of female-biased SSD among terrestrial animals, as far as we know.”

The Jason Bond lab and the Chris Hamilton lab, Department of Entomology, Plant Pathology and Nematology at the University of Idaho, Moscow, provided the anchored hybrid enrichment data and phylogenomic analysis.

Co-authors of the paper, in addition to Bond and Hamilton, are

• Matjaž Kuntner of the National Institute of Biology, Ljubljana, Slovenia; the National Museum of Natural History, Smithsonian Institution, Washington D.C.; and Hubei University, China;
• Ren-Chung Cheng, Biological Institute ZRC SAZU, Ljubljana, Slovenia, and National Chung Hsing University, Taiwan;
• Matjaž Gregorič, Nik Lupše and Tjaša Lokovšek, all with the Biological Institute ZRC SAZU, Ljubljana,Slovenia (Lupse is also affiliated with the Charles University, Prague, Czech Republic);
• Emily Moriatry Lemmon and Alan Lemmon, Florida State University, Tallahassee;
• Ingi Agnarsson of the National Museum of Natural History, Smithsonian Institution; and University of Vermont, Burlington; and
• Jonathan Coddington, National Museum of Natural History, Smithsonian Institution.

The research drew funds from Slovenian Research Agency grants, from the U.S. State Department through a Fulbright visiting scholar; ZRZ Director's Fund, National Science Foundation, Doctoral Dissertation Improvement Grant and funds from Auburn University, Alabama. Bond joined the UC Davis faculty in July of 2018 from Auburn University after a seven-year academic career there, where he served as professor of biology and chaired the Department of Biological Sciences. He also curated the arachnids and myriapods (centipedes, millipedes, and related animals) at the Auburn University Museum of Natural History.