It's surprising what the microbes in nectar can reveal.

Take the nectar of the sticky monkeyflower, Mimulus auranticus.

UC Davis community ecologist Rachel Vannette and colleague Tadashi Fukami of Stanford University decided to examine microbial communities inhabiting the nectar of the sticky monkeyflower at the Jasper Ridge Biological Preserve in California's Santa Cruz Mountains.

Their paper, "Dispersal Enchances Beta Diversity in Nectar Microbes," published in Ecology Letters, revealed that contrary to popular assumption, “increased dispersal among habitats can actually increase biodiversity rather than decrease it."

The flower, in the family Phrymacease, is a native shrub common in chaparral and coastal scrub habitats of California and Oregon. It is primarily pollinated by Anna's hummingbird. Other common pollinators include bumble bees, carpenter bees, and thrips.

Dispersal is considered a key driver of beta diversity, which is “the variation in species composition among local communities,” Vannette said.

They are the first to publish work showing that increased dispersal can increase biodiversity. 

In their experiment, they reduced natural rates of dispersal by eliminating multiple modes of microbial dispersal. “Specifically we focused in nectar-inhabiting bacteria and yeasts that are dispersed among flowers by wind, insects and birds,” they said. “We imposed dispersal limitation on individual flowers and quantified microbial abundance, species composition and microbial effects on nectar chemistry.”

The scientists “manipulated dispersal of nectar-inhabiting bacteria and yeasts via flower-visiting animals to examine how dispersal influenced microbial beta diversity among flowers. Our analysis suggested that this unexpected pattern might have resulted from stronger priority effects under increased dispersal.”

This work has direct implications for conservation of many organisms in addition to bacteria and yeast, suggesting that preserving routes of dispersal among habitat patches may be important in the maintenance of biodiversity. In contrast to previous work showing that dispersal can homogenize communities or make them more similar, the published work demonstrates that dispersal can in some cases generate communities that are more different from each other. The authors hypothesize that this could be driven by priority effects, where early arriving species change the species that can establish within that habitat.

Why focus on nectar-inhabiting microbes? Previous work by Vannette and others shows that microbial activity in nectar can alter nectar chemistry and influence plant-pollinator interactions by altering nectar chemistry. In the Ecology Letters study, microbes were also found to change nectar chemistry, explaining ~50% of the variation in sugar composition in the field. This suggests that nectar-inhabiting bacteria and yeast can influence the nectar rewards available to pollinators in a natural setting.

More broadly, “Studying the role of microbes in the environment addresses one of the biggest mysteries in science,” Vannette says. In her current work, she and her lab are investigating how microbial communities form, change, and function in their interactions with insects and plants. They are also researching how microorganisms affect plant defense against herbivores and plant attraction to pollinators.

Vannette, a former postdoctoral fellow at Stanford, joined the UC Davis Department of Entomology and Nematology faculty as an assistant professor in 2015.

Vannette's research was funded by the Gordon and Betty Moore Foundation through the Life Sciences Research Fellowship. Stanford also funded the research through grants from the National Science Foundation, the Terman Fellowship, and the Department of Biology at Stanford University.

So, here we are, a couple of stink bugs hidden in the lavender. Unnoticed. Undetected. Undisturbed.

We're loving the lavender, and we're in the process of providing the world with more stink bugs.

"Okay, we know, we know. We're red-shouldered stink bugs (Thyanta pallidovirens). You humans named us but you don't define us.  You guys think we're pests and are always trying to research our reproductive behavior. And you're bound and determined to control us and our offspring.

"But, could we just ask for some privacy, please? Oh, what's that sound? Sounds like a buzz saw coming right at us!"

The honey bee touches down next to them and stops to sip some nectar. Her antennae brush against the couple. "Move!" she says to the stink bugs. "I'm trying to work here."

Nobody moves but the bee.

It's no fun having a "hole in one."

No, not golf.

A hole in your butterfly habitat.

So, here it is September of 2016 and we're at home rearing monarch butterflies as part of our small-scale conservation project to help the declining population. 

The project involves growing several species of milkweed in our pollinator garden, and when we see caterpillars, we "bring them in." We fill a broad-based, narrow-necked Patron tequila bottle with water, add milkweed and 'cats, and tuck the bottle inside a zippered, pop-up mesh habitat (some call it a cage) to protect them from predators (like birds) and parasitoids (like tachinid flies). The butterfly habitat occupies a corner of our kitchen counter.

When the monarchs eclose, we release them back into our pollinator garden, which is filled with nectar-rich Mexican sunflower (Tithonia) and butterfly bush (Buddleia davidii).

So, one day in September, I think: "Why keep the monarch habitat on our kitchen counter when it's so nice and shady and breezy by the crape myrtle tree in our backyard?"

So, I place the habitat on a wooden bench next to the crape myrtle.  Ah. Mother Nature at its finest. Several caterpillars are in the "J" position (their position before they pupate) and several are chrysalids.

All's right with the world, right? Wrong.

The unexpected happens. The caterpillars begin shriveling.  The chrysalids turn gooey brown. And right before my eyes--I happened to be in the yard at the time--I see tachinid fly maggots "bungee jumping"  from their hosts.  The maggots are sliding down their white mucus strings. Gleefully sliding, I think.

What?

Tachinid flies, you see, lay their eggs inside a living host, such as a monarch caterpillar or chrysalis. They eat the host from the inside out, kill the host, and maggots emerge. They're white at first but darken and harden to the color of coffee beans as pupae. The adult flies emerge, all ready to mate and start the life cycle all over again.

But how did they get into the thinly meshed habitat? How?

It is then that I notice a single, tiny, ragged hole in the netting. And oh, look! Another tachinid fly is trying to slip in.

I photograph Exhibit A, B, C and D; clean the cage with bleach and water; and vow that the butterfly habitat is best inside, not outside.

A hole in one is no fun.

Ready for those June weddings?

Coming to an altar near you...a bride and a groom. "When you marry in June, you're a bride all your life."--Anonymous.

"Look happy," say the wedding photographers as they focus on the bridal couple, and then single out the bride who will be a bride all of her life.

But if you engage in insect wedding photography, you'll find that June is a good month for insects, too. 

Take those tachinid flies. Have you ever focused on them?

Monarch moms and dads--those who rear and release monarch butterflies--hate tachinid "weddings." They hate the bride, the groom, their families, and all future offspring.  It's a hate-hate relationship.

That's because some members of the Tachinidae family are parasitoids, that is, the flies lay their eggs inside a living host (larva). The fly larvae eat the tissue from the inside out, killing the host.

That's good if you're trying to control cabbage white flies, cabbage loopers, alfalfa loopers, fall armyworms, variegated cutworms, codling moths, oriental fruit moths, peach twig borers, obliquebanded leafrollers, omnivorous leafrollers, oriental fruit moths, peach twig borers, pink bollworms and other pests. It's a "natural enemy" thing. See UC Statewide Integrated Pest Management Program.

That's bad if you're trying to rear monarch butterflies. You're appalled when your caterpillar shrivels and dies, and several fly maggots emerge. Or when your brown-stained chrysalis turns to goo, and out pop several maggots.

But back to insect wedding photography. We've never managed to catch tachinid flies feeling a little...uh...well...amorous. This amorous feeling is not mutual; to be honest, I still haven't forgiven them for what they did to our small-scale, rear-and-release monarch project last year. 

Still, as a insect photographer, I consider myself a guest in their habitat. 

So, yes, I walked away. I did. No insects were harmed in the making of these photographs.