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The Bug Report: A Plant Is Worth a Thousand Bugs
By: The Invertebrate Ecology Conservation Team
A Survey of San Clemente Island’s Plant-associated Invertebrates
In 2019, Santa Barbara Botanic Garden conducted a survey of insects, spiders, and their invertebrate kin (collectively, “bugs”) on San Clemente Island. Of California’s eight Channel Islands, San Clemente is one of the most remote and least accessible, possessing a rich flora of rare and endemic plants. We collected bugs associated with these plants using an oldie-but-goodie entomological method called beatsheeting. Here’s a more than thorough description of the method: You place a sheet underneath a plant, hit the plant with a stick, and collect the bugs that fall onto the sheet.
Taxa Codependency
The island’s plants support bugs that feed, breed, and live on them, and the island’s bugs support plants through pollination and other services. To better understand these relationships, beat-sheeting was repeated at sites across San Clemente, and bugs were collected from a variety of plants in different habitats. The bug-plant co-occurrence data gleaned from this approach (i.e., what bugs were found on what plants) can ultimately help us better protect the Channel Islands’ distinct flora and fauna. For example, we collected specimens of a bark beetle new to science, Carphobius caterinoi, (Cognato & Smith) exclusively on island oaks (Quercus tomentella), suggesting the survival and reproduction of these beetles is dependent on the endemic oaks.
Divide and Curate
We found a lot of bugs, looked closely at a lot of bugs, and photographed a lot of bugs, many recorded on San Clemente Island for the first time (Phillips et al., 2023). Such intensive bug work can transform anyone into a connoisseur of fine insects (e.g., bees and butterflies), or even an enthusiast of Two-Buck Chuck creepy-crawlies (e.g., ants and cockroaches). Without exception, the Garden staff and volunteers who helped on the project became bug ambassadors, each developing an affinity for certain groups of invertebrates. Kylie Etter became a wasp whisperer, José Flores earned his bad beetle-boy badge, Jordan Sanderson took a long trip on the thrips train (last stop: more thrips), Laiken Warner and I gazed into the eyes of arachnids, and Denise Knapp, Ph.D., swarmed the flies.
In the gallery that follows, we each share some of our favorite bugs from the survey and describe one of the tools we used to identify, curate, or photograph said bugs. The photos represent just a few of the approximately 55,000 individuals we collected, belonging to 695 morphospecies (morphospecies are hypothesized species based on morphological characteristics), 201 families, and 33 orders. You can view more photos on the survey’s iNaturalist page, a publicly accessible digital collection of specimens (“2019 SBBG Terrestrial Inverts of San Clemente Island” project at iNaturalist.org). If you’d like to get involved with similar projects at the Garden, contact me about bug volunteer opportunities (zphillips@ SBBotanicGarden.org).
Take a look at some of the 48 plant taxa on which we collected bugs during the survey, including rare and endemic Channel Island species and subspecies.
Kylie Etter, Conservation Technician
Metaphycus wasp (Order Hymenoptera) specimen collected from coyote bush (Baccharis pilularis)
Most of the world’s wasp diversity is made up of tiny parasitoid wasps, like this one (Metaphycus sp.). Parasitoid wasps grow on or inside their hosts as juveniles and they must kill their hosts to complete their lifecycle. (This is what distinguishes parasitoids from parasites, which don’t have to kill their hosts). Due to the hyper-diversity and tiny size of parasitoid wasps, they can be difficult to identify. I was only able to identify this specimen to family (Encyrtidae), but after posting these photos on BugGuide.net, a wasp expert was able to identify it to genus. He also noted that this might be an undescribed species, which means it has not been formally described and named.
Phygadeuontini wasp (Order Hymenoptera) specimen collected from island buckwheat (Eriogonum grande var. grande)
Can you spot the wasp among the acrobat ants (Crematogaster sp.) in this picture? I don’t know why she is pretending to be an ant, but I am sure it’s to her benefit!
The wasp is a parasitoid wasp in the Family Ichneumonidae. Compared to the ants, it has long antenna with numerous segments, a smaller head, bigger eyes, and a long ovipositor (a long, specialized organ used to deposit eggs) extending out from the end of its abdomen.
Urbane Digger bee (Order Hymenoptera) specimen collected in chaparral woodland
The Urbane Digger bee (Anthophora urbana) can be found on the mainland, but this subspecies, Anthophora urbana ssp. clementina, is an island endemic. The island subspecies has rusty red colored hair, while the mainland one has more blond hair. Anthophora urbana ssp. clementina visits some of the island’s rare plants such as San Miguel Island milkvetch (Astragalus miguelensis), leafy desert dandelion (Malacothrix foliosa ssp. foliosa), and San Clemente Island bush mallow (Malacothamnus clementinus).
Mason bee (Order Hymenoptera) specimen collected on the ground
We collected 15 specimens of Osmia aglaia from the island, a species previously not recorded as being on San Clemente. It’s important to do insect surveys consistently to track population numbers, understand community structure, and record new species either recently introduced to the island or that have been missed in past efforts.
Paintbrush
The paintbrush is my favorite all-around go-to tool while doing insect sorting, identification, and photographing. It can gently separate insects from one side to the other in a petri dish of ethanol, pick up insects and move them from vial to vial, and brush off any dirt or dust clinging onto pinned specimens interfering with getting the perfect picture.
José Flores, Conservation Technician
California ladybeetle (Order Coleoptera) photographed on San Clemente Island buckwheat (Eriogonum giganteum var. formosum)
The California ladybeetle (Coccinella californica) is a species of ladybeetle that exists along the coast from Baja California, Mexico, to southern Alaska. They’re easy to identify from their spotless forewings (called “elytra”), and a dark band running vertically across their elytra. Overall, ladybeetles are a nice guest to have around your home garden. They may not look like voracious predators to us, but they eat a lot of aphids, including the pesty aphids that can infest garden plants.
Johnson’s ladybeetle (Order Coleoptera) photographed on golden yarrow (Eriophyllum confertiflorum)
Johnson’s ladybeetle (Coccinella californica form johnsoni) is a form of ladybeetle that exists on islands along the western United States and Canada, including the Channel Islands. It has five large spots on each forewing and one spot being shared between the forewings, giving it a total of 11 spots. Sometimes the two spots in the back appear to be coalescing into one giant spot.
Kidney-spotted fairy ladybeetle (Order Coleoptera) specimen collected from coyote bush (Baccharis pilularis)
Lady beetles (Family Coccinellidae) are diverse. This kidney-spotted fairy ladybeetle (Psyllobora renifer) has the same general shape as the other ladybeetles collected on San Clemente Island, but it exhibits a distinct color pattern on its hardened forewings.
Ladybeetle larva (Order Coleoptera) specimen collected from island morning glory (Calystegia macrostegia ssp. amplissima)
Before a ladybeetle (Family Coccinellidae) matures into an adult and develops its wings, it looks like this. Like adult ladybeetles, the larvae feed voraciously on aphids that feed on plants. Insect larvae are generally more difficult to identify than adults, and the vast majority of insect identification keys and guides are based on adult features, not larval ones. This is one of the reasons we generally didn’t include larvae in our survey.
BugGuide.net
We post images of some of our specimens on iNaturalist.org, a well-known nature website and app used to share images and information about all kinds of animals and plants, and on BugGuide.net, a website used in a similar fashion but exclusively for “insects, spiders, and their kin.” BugGuide has been around since 2003, and it is where a lot of experts have congregated to help identify these invertebrates. The website also serves as a great learning tool as each unique species, genus, etc., has its own page that is curated by frequent users where they can add information such as identification tips, species ranges, and a list of print and internet references, to name a few. For our San Clemente Island invertebrate project, we posted on BugGuide only if iNaturalist did not assign an ID to a specimen’s taxonomic family within a week. Like iNaturalist, identification on BugGuide is all based on volunteer time, so we do not expect an immediate response, but we always get excited when our tougher-to-identify specimens are identified.
Jordan Sanderson, Volunteer
Thrips (Order Thysanoptera) specimen collected on island buckwheat (Eriogonum grande var. grande)
Over half of the insects that were collected on San Clemente Island are thrips (Order Thysanoptera), which have close associations with plants. They’re hard to see with the naked eye, especially their feathered wings and the hairs all over their body.
Thrips (Order Thysanoptera) specimen collected from bush sunflower (Encelia californica)
Thrips (Order Thysanoptera) specimen collected on blue dicks (Dipterostemon capitatus)
Springtail (Order Collembola) specimen collected on California sagebrush (Artemisia californica)
Like thrips, springtails (Order Collembola) are a ubiquitous but often overlooked group of tiny animals. Springtails are closely related to insects, but they don’t have jointed appendages like insects do.
Springtail (Order Collembola) specimen collected on common fiddleneck (Amsinckia menziesii var. intermedia)
Springtail (Order Collembola) specimen collected on California sagebrush (Artemisia californica)
Dissecting scope
Sorting through all the insects in this project would have been impossible without the help of a dissecting microscope. This scope allows 3D views of teeny tiny objects and allows invisible details to be seen as clear as day. It also allowed us to orient bugs properly before placing them under the microscope camera and photographing them.
Laiken Warner, Volunteer
Leafhopper (Order Hemiptera), with a parasitoid wasp attached (Order Hymenoptera) — specimen collected on island tarplant (Deinandra clementina)
This leafhopper (Family Cicadellidae) should choose its friends more carefully. The dark blob attached to its side is a parasitoid wasp larva. At this stage, both the leafhopper and wasp are juveniles. Eventually, the wasp will emerge as an adult, mate, and if she’s female, find more leafhoppers to deposit her eggs in.
Phidippus jumping spider (Order Araneae) specimen collected from coastal prickly pear (Opuntia littoralis)
Have you ever seen a spider sparkle? This is the distinctive face of a jumping spider (Family Salticidae), and the sparkle is coming from its chelicerae, or jaws. Jumping spiders don’t capture prey in webs. Instead, they actively track them down, and their two large, forward-facing central eyes help them hunt.
Mecaphesa crab spider (Order Araneae) specimen collected from San Clemente Island paintbrush (Castilleja grisea)
Here’s a peek into the arachnid cardiovascular system. Spiders have hearts too, you know! This crab spider (Family Thomisidae) was collected from the endemic plant San Clemente Island paintbrush (Castilleja grisea), where it may have been waiting to pounce on visiting pollinators.
Hand sanitizer
Hand sanitizer is the unsung hero of the invertebrate imaging world. The humble sanitizer holds bugs in position while taking a photo with the microscope. And when you need to move the bug to get another angle, it’s easy to do. For the project, we typically took at least three photos of each specimen: one from above (dorsal), one from below (ventral), and one from the left side (lateral) of the bug.
Zach Phillips, Ph.D., Terrestrial Invertebrate Conservation Ecologist
Metepeira orbweaver spider (Order Araneae) specimen collected on San Clemente Island hazardia (Hazardia cana)
Spiders are astute botanists, and they use their ancient knowledge of plants to hide and hunt more effectively. They camouflage themselves against flowers, anchor webs to stems and branches, and hop around vegetation seeking prey. This fuzzy Metepeira spider is in the orbweaver family (Araneidae), a group that decorates San Clemente’s plants with silken traps.
Jumping spider (Order Araneae) specimen collected on coyote bush (Baccharis pilularis)
Jumping spiders (Family Salticidae) get a lot of media attention because they’re adorable — and they know it. As if this spider’s head wasn’t big enough already, you can see an enlarged copy of this photo on a wall in the Pritzlaff Conservation Center Gallery at the Garden.
Ghost spider (Order Araneae) specimen collected from Blair’s wirelettuce (Munzothamnus blairii)
Some of the spiders we collected on San Clemente feed directly on plants. In addition to eating bugs, ghost spiders (Family Anyphaenidae) drink nectar from flowers to help fuel their active lifestyle.
Stilt bug (Order Hemiptera) specimen collected from island tarplant (Deinandra clementina)
What a bug. Its long legs are characteristic of the family it belongs to, the stilt bugs (Berytidae). It was collected from island tarplant, where it was likely using its straw-like mouthparts to suck some of the plant's juices, or scavenging other insects stuck to the plant's surface. The stilt bug’s spines and long legs help it avoid a similar fate, enabling freer movement through a plant’s sticky and clingy hairs.
Leafhopper (Order Hemiptera) specimen collected from San Clemente Island buckwheat (Eriogonum giganteum var. formosum)
This leafhopper (Family Cicadellidae) likely represents a new species to science. If she seems bland, it’s not her fault. Blame us. Her natural colors have been washed away by the ethanol in which she was stored. She uses the long, bladelike ovipositor at the end of her abdomen to lay eggs inside of plants. We don't know which plants, but our survey results suggest a few candidates, including San Clemente Island buckwheat.
Coffee
We need to talk. Yes, it’s serious. I don’t ever want to see your ugly mug again. Sure, I remember the good times. We’ll always have the jitterbug, you and I — we danced like it was nobody’s business! I held the bugs, and you made them jitter. But that doesn’t change a thing. The project is over, and I need to sleep. You’re out; chamomile is in. I’m telling you SCRAM, bub! You may not be single origin, but you’re single now, got it? I don’t care where you go, just lose my number and stop sending me latte art. Wait, don’t leave … maybe just one more sip.
Denise Knapp, Ph.D. Director of Conservation and Research
Bee Fly (Order Diptera) specimen collected from California golden violet (Viola pedunculata)
Bee flies (Family Bombyliidae) are the reason I went back to graduate school. While working as a plant ecologist on Catalina Island, I would watch them and wonder what they were. There I was, trying to protect an array of very rare plants, and I didn’t know who their pollinators were. Bee flies are not only adorable and effective at pollinating while they stick their long mouthparts into a deep-throated flower, but they also have a cool edginess: their larvae are parasitoids of other insects, especially bees. This one (Bombylius major) was collected from California golden violet (Viola pedunculata).
Robber fly (Order Diptera) specimen collected on a rock
Everything about this robber fly (Family Asilidae) says “predator.” The piercing mouthparts, huge eyes, and copious strong bristles are most obvious. It takes more observation, though, to see these venomous, athletic flies catching and sedating their prey, and then sucking out the contents of their bodies, all while on the wing. They have a long mustache called a mystax that protects them from their flailing victims.
Cactus fly (Order Diptera) specimen collected on island false bindweed (Calystegia macrostegia)
One reason I love flies is that they do so many jobs that benefit ecosystems and people. They pollinate flowers, help control pest populations, and, among other things, act as saprophages that break down dead and decaying matter. The cactus fly pictured here (Odontoloxozus longicornis) is a saprophage, and commonly feeds and breeds in rotting cactus. Although there is only a single species of cactus fly recorded from the United States, regional populations exhibit distinct genetic variation, including those on the Channel Islands.
Fly books
The most important tool for me when identifying flies is a good dichotomous key, with descriptions and illustrations that help me decide if I got it right or not. “Flies: The Natural History and Diversity of Diptera” by Stephen A. Marshall has a wonderful, user-friendly key with drawings of important features, along with excellent natural history information and photographs. “The Manual of Nearctic Diptera” volumes, authored by numerous experts, have many illustrations of the different groups and important features like wing venation, bristle patterns, and facial features.
Citations
Cognato, A. I., & Smith, S. M. Taxonomic review of Carphobius Blackman, 1943 (Curculionidae: Scolytinae) and a new species from San Clemente Island, California, U.S.A. The Coleopterists Bulletin. (In review)
Phillips, Z. I., Flores, J. M., Etter, K. J., Lee, C., Calloway, S. M., Searcy, A. J., Sanderson, J., Warner, L., Zhang, D., Trujillo, S. H., Makler, L. C., Zendejas, S., Noroian, H. M., Martín, A. J., Cusser, S. J., & Knapp, D. A. (2023). San Clemente Island Terrestrial Invertebrate Survey: Guiding Biodiversity Inventory, Rare Plant Conservation, and Habitat Restoration. Report prepared for U.S. Navy by Santa Barbara Botanic Garden.
