Words by Sophie Citro PZ ’30

Graphics by Penny Messinger SC ’29

If you’ve so much as glanced out a window in the past few weeks, you are likely aware of the huge green beetles zipping around Claremont. They’re hard to miss with their erratic, clumsy flight patterns and striking iridescent elytra. These are the fig (or figeater) beetles — Cotinis mutabilis, or, rarely, texana — a type of scarab beetle native to the Ssouthwestern United States and much of northern South America. Contrary to what many people will tell you, they are not June bugs (those are Cotinis nitida, which are similar in appearance but not found in the western United States), and, more importantly, they are not going to bite you. However, in recent years, these conspicuous beetles have started showing up earlier in the season. Is this the result of climate change? Why does it matter?

To answer these questions, we’ll turn to Wallace Meyer, a professor of biology at Pomona with a focus on conservation and invasion biology, and director of the 5Cs’ Bernard Field Station. He says he finds “multiple things interesting” about fig beetles: “what cues them to become adults and start flying around,” and “what factor[s] influence their abundance and timing,” among others. Fig beetles do indeed have a fascinating life cycle. Although we mainly see them in their shiny green adult forms, they in fact spend the majority of their life underground as grubs. Grubs are the larval form of a beetle, and typically have fleshy white bodies with a dark brown head and little stubby legs (though these larvae prefer to wiggle around on their backs.). After hatching from small white eggs laid in fall, the grubs spend their first instar — a period of time between molts — munching on the bottom levels of leaf litter. During their second and third instars, they dig themselves a tunnel up to two feet deep, which they then pupate in, emerging as adults in late summer. This stage comprises the majority of their life cycle, yet they are almost never seen: the grubs travel only under cover of dead leaves, avoiding light and exposure to predators and clumsy humans.

It is also important to note that at no point in their life cycle do fig beetles have any hint of a desire to attack people. “[Students] should recognize that they are poor fliers and have no desire to attack a human. They are just bumbling their way th[r]ough life looking to find a mate. They do not bite and are not predators,” explains Meyer. The only way in which they disrupt humans is by eating soft fruit, such as figs — hence their name — and grapes, which, even if one is a hungry beetle, cannot possibly be mistaken for college students. It’s common to hear yelps of fear or even see students swat at them as they cruise past, but they’re not going to hurt you. The easiest way to get rid of one is simply to leave it alone — or, if you’re a bug person like me (or just feeling adventurous), you can hold out a handful of water and watch them land for a drink.

Their life cycle can tell us a lot more about climate change than one might think. As Meyer states, “they could[,] depending on what cues they use to become adults[,] tell us a lot about how they and other organisms, especially insects, may be impacted by cli[m]ate changes.” This is an example of phenology — the study of when natural events occur, such as flowers blooming or trees fruiting. Since larvae use environmental cues such as humidity and temperature to decide when to pupate, changing pupation times might indicate anything from unusual precipitation patterns to unbearable heat to uncomfortable cold. “I think [it] would be good to track when we see them flying around and[ ]when we don’t,” says Meyer, but “you would have to do this over many years to have any concrete conclusions.” This is a major issue in long-term environmental studies: it takes years to get results, and in a time where federal budget cuts and iffy funding is more common than ever, in many cases it is simply not feasible anymore.

Despite being so hard to study, these topics are also unfortunately some of the most important. Phenology is crucial in understanding climate change. “Timing is everything. If [an] organism[’]s timing is off[,] it changes many aspects of how ecosystems function. For example, if a pollinator is flying at a time a plant is not flowering, then it is possible that the plant may not create viable seeds. This is why there are so many unknowns with regard to the effects of climate change on biodiversity,” Meyer explains. Beyond just their economic significance, fig beetles are important to southern California’s ecology. “Their dead bodies represent a flux of nutrients into the system,” says Meyer, and while alive they provide food for skunks (as adults) and some birds (as larvae). They’re even accidental pollinators — look closely at one, and you’ll see fine coppery hairs on the abdomen upon which pollen can collect. Additionally, if fig beetles are making noticeable changes in their life cycles, they are likely not the only ones. What happens if California’s solitary bees start emerging later, missing the flowers they specialize in? What if wild bushes finish fruiting earlier, creating stretches of time with less available food?

Another indicator of widespread change in climate is range expansions. Fig beetles are typically restricted to southern areas of the U.S., but in recent years, hotter weather has allowed them to expand northward. Records show them as far north as Utah in the 2000s and Colorado in 2012, which could have adverse effects in the form of crop damage or competition with native species. This is a pattern occurring worldwide– look at Washington’s bumblebee Bombus vosnesenskii, which went from an endangered species candidate to outcompeting B. occidentalis in a matter of years, or the uptick in hornet (wasps in the genus Vespa) sightings on the East Coast, where V. velutina and crabro seem to have found suitable habitat.

Whether or not a phenological change or range expansion poses significant immediate harm to the environment, it is still a large shift that can disrupt an ecosystem’s balance. “There are so many unknowns with regard to the effects of climate change on biodiversity,” says Meyer, and with the current state of research funding, they are likely to remain unknowns. Our shiny, gentle green fig beetles are just a small part of a much larger picture… one that unfortunately, for the time being, remains obscured.