Who Run the (Insect) World? GIRLS

“I woke up like this. Flawless.” – Beyoncé

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Insects dominate the animal kingdom. They occupy every niche imaginable and have evolved to make meals of every substance available. Winged or wingless, aquatic or terrestrial, solid or fluid feeders, insects have acquired the flexibility to adapt to their surroundings quickly. They are opportunistic, industrious, integral to our ecosystems, and innumerable. And here’s the thing.  It’s the female insects that have evolved ingenious ways to control their bodies, make a living, defend themselves, and secure unique food resources. Cheers to all the six-legged single ladies that are fiercely running the insect world!

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Female praying mantis. Photo: Susan Beebe

 Reproductive Choice

No boys? No problem!  Parthenogenesis is a means of reproducing sans males, and sans copulation. It translates from Greek as ‘virgin creation’. Females simply lay egg clones of themselves. Short horned walking sticks, in addition to certain species of aphids, weevils, flies, roaches, and grasshoppers have dispensed with males completely. Parthenogenesis isn’t just an invertebrate phenomenon, either. It’s been documented in reptiles, amphibians, fishes, and sharks. In fact, in eschewing males for reproductive purposes it seems that mammals are the only animal group without any known naturally occurring cases of virgin birth!

For females that do require the deed to get offspring, some species can still retain control over the timing of motherhood. Sperm storage is a common reproductive strategy in the insect world. After mating, females retain sperm packets in a specialized internal purse until she chooses to fertilize her eggs. Not only can she control the timing of fertilization, but after copulating with many males, she can choose which sperm she utilizes in a strategy called cryptic female choice. Manipulating paternity not only comes from her mating choices, but afterwards, in sperm choice! It goes to show that sometimes it does pay to play around.

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Adult walking stick with 2 clones. Photo: ASDM/Catherine Bartlett

Self Defense

Opulent males are often dressed up in the bug kingdom with thorny adornments and garish horns. But their jewelry isn’t as impressive as a female’s defensive weapon.  The sting is the thing that can pack a punch- and only the females can do it. A stinger is a modified ovipositor, that is, an egg laying device. But for social bees, wasps, and other flower foragers, the ovipositor isn’t used for egg laying, rather, it’s employed to inject venom. Not all stings are created equal though. The amount and toxicity of venom injected can drastically increase an arthropod’s ranking on the Schmidt Sting Pain Index. Yes, someone (a Tucsonan, in fact)  purposefully stung himself and graded the outcomes! Pain is ranked from 0 (no pain) to 4 (traumatic pain). Honey bees earned a two while pepsis wasps (a.k.a. tarantula hawk wasps) and the aptly named bullet ant earned a ranking of four.  Male bees, wasps, and ants get off scot free: while they can’t sting, they do mimic the coloration of females, and are thusly avoided by predators as well.

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Tarantula hawk wasp. Photo: Don & Shea Sorensen

Women in the Work Force

Apples. Oranges. Squash. Almonds. Honey. Thank a bee for the services she provides to the food economy every year via pollination. Every third bite of food we take can be attributed to a bee, and Tucson is the Hymenopteran epicenter. Although the honey bee is an introduced species, Americans have become reliant upon its services for crop pollination.  In 2010 honey bees were responsible for pollinating $12.4billion worth of directly dependent crops in the United States and the vast majority of bees in a hive are female. The workers are  women that leave the home, forage, waggle, collect, and transport resources. It’s rare to spot a male honey bee as the drones are used solely for reproductive purposes. Food on your plate and mead in your glass? Thank a busy buzzer!

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Honey bee. Photo: Rhonda Spencer

Making a Meal

It’s a well-known trope that lady praying mantids decapitate and eat males after sex. This is quite often true, especially in captivity. But what other sneaky strategies exist? Let’s look at the luminous fireflies. Male fireflies advertise their prowess by rhythmically flashing to females. Usually this happens en masse and the pulsating of many young virile beetles is quite attractive to females, who respond with flashing of their own. The flashiest male gets the girl. It’s easy to imagine that the Justin Timberlake of the fireflies would get more attention than the rest of ‘N Sync in the insect version of a flash mob dance-off.  However, females of Photuris versicolor, a variety of firefly, will mimic the exact photic signaling of males of other firefly species. This trickery attracts naive females looking for love. Instead of finding a beetle boyfriend, they themselves become the grub!

Females in the animal kingdom are fundamentally conditioned to be selective- about everything from mate choice to breeding location to food sources utilized. Being a female is expensive and dangerous and selectivity equals survival. Insects especially are subject to pathogens, predators, climate change, pesticides and human destructivity. However, these creatures have been strategically evolving for hundreds of millions of years proving that regardless of challenges faced, nevertheless, the ladies persist.

Written by ASDM Education Specialist, Catherine Bartlett. 


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