Warm weather to bring out more bugs

Gig Conaughton

County of San Diego

Communications Office

Get ready for “buggy” spring – part two. You might be thinking that after weeks of unseasonably, unexpected, wintry cold weather around San Diego County we’ve seen the last of this spring’s increased numbers of insects.

Maybe.

But it’s more likely that the cold is just a speed-bump for our “buggy” spring and that we’ll continue to see lots of bugs when normal spring temperatures return in the coming days. That’s because bugs are still chowing down on green growth produced by the county’s rainiest winter in years, county of San Diego officials said this week.

“All this (cold) may do is delay things a little bit,” Chris Conlan, the county of San Diego’s supervising vector ecologist and bug-watcher by trade, said. “The other thing to remember is that we also got some rain with the cold snap, and that may actually recharge some of the plants out there and make them last a little longer.”

Conlan said the food chain equation is simple. Lots of rain produced lots of plants that bugs use for food. And lots of food has generated lots of bugs.

In March, local media and residents were abuzz over seeing large numbers of crane flies – large, spindly, crazy-flying insects that look like supersized mosquitoes, but are not and are actually harmless. In April, hummingbird moths made the news. They are also known as Sphinx moths or hawk moths, which fly like hummingbirds and are nearly as large.

So what insects may surprise us all next? Conlan said it’s hard to say. It is something that could change from location to location depending upon where people live around the county. Mother Nature, he said, is always unpredictable. Conlan said the spring population booms of crane flies and hummingbird moths are probably in the rear-view mirror, but that there are still lots of different kinds of bugs feasting on lots of plants.

County entomologist Tracy Ellis with the county’s Department of Agriculture, Weights and Measures said homeowners and garden owners may start seeing more – or at least, evidence of more – garden snails and slugs. Ellis said they tend to hide during the day and munch on garden plants at night.

“They grow on weeds and then move into yards and leave mysterious holes in leaves and on homeowner’s plants,” Ellis said.

A bee squeezes into an agapanthus flower to collect nectar.

Conlan said it is possible that county residents could start noticing increased numbers of tiny – and harmless – crawling bugs that feast on native weeds as temperatures rise and those food sources dry up.

Bugs like false cinch bugs, bagrada bugs and red bugs – scantius aegyptius – which alarmed people and made the news when they were found around the county for the first time in 2014, will crawl into people’s yards if their regular food sources die.

“You’ll get situations,” Conlan said, “where they build up into very large numbers on those plants, and when that food source is no longer viable, they migrate into neighborhoods and freak people out.

“People have sent me pictures of them,” he said, “literally hundreds and hundreds of them, all over the front of the house or just coating the top of their pools.”

Conlan said the best way to prevent that is to mow down weeds before they get large and dry out. But he also said people should remember not to freak out. Most bugs in the county – with the exception of vector bugs like mosquitoes that can transmit disease – are harmless to people.

And, he said, as spring wears off and food plants dry up, nature takes over.

“If there’s nothing for them to really feed on,” Conlan said, “they just kind of eventually die off and go away.”