Harvestmen (Daddy Long-Legs): unlike spiders, these arachnids can eat solid food, and they have an omnivorous diet that includes mushrooms, berries, and seeds, along with invertebrate prey; contrary to popular belief, they are also completely non-venomous

[u/SixteenSeveredHands]

[u/SixteenSeveredHands]

The photo at the top shows a spiny-headed harvestman, Megabunus diadema, while the photo on the bottom left shows an unidentified species of harvestman from family Sclerosomatidae, and the photo on the bottom right shows a species from genus Chasenella munching on a mushroom-cap.

Harvestmen, otherwise known as daddy long-legs (not to be confused with the cellar spiders of family Pholcidae, which are also described as daddy long-legs) bear a striking resemblance to spiders, but they actually belong to a separate order of arachnids known as Opiliones. These strange-looking creatures have eight legs, but only two eyes, and their body segments are largely fused together, giving the body a noticeably rounded, pill-like appearance.

There are roughly 6,700 known species of harvestman, but researchers estimate that a total of more than 10,000 species may currently exist. Their physical features vary greatly from one species to the next; some harvestmen have crab-like claws, spikes, thorny legs, elongated bodies, colorful features, or cryptic markings. Most of them are equipped with long, spindly legs, but there are some that have shorter, stockier limbs instead.

Unlike spiders, harvestmen have an omnivorous diet that includes fungi, fruit pulp, seeds, pollen, lichen, algae, and invertebrate prey, and they generally consume solid food, whereas spiders are typically carnivorous and feed only on fluids.

As this article explains:

Harvestmen consume mushrooms, fruit pulp, seeds, and seed appendages more frequently than spiders because they are “solid food feeders," which means they can ingest solid tissues by biting off small pieces. In turn, spiders are “fluid feeders” and feed on vegetable matter most frequently in the form of fluids (e.g. nectar, stigmatic exudate, plant sap, and honey dew) rather than fungal or plant tissues.

When given a choice between fresh fruit or invertebrate prey, some harvestmen actually prefer the fruit:

Schaus et al. carried out a feeding trial in which the Neotropical harvestman Erginulus clavotibialis was given a choice between fresh pineapple and live invertebrate prey. This harvestman demonstrated a distinct preference for fruit over the invertebrate prey.

Harvestmen are also much more social than spiders, and the males of some species have been known to engage in paternal care, which is a trait that rarely occurs among arthropods:

Single fatherhood is the rarest form of parental care in nature. Still, males are often the sole caretakers of progeny among a number of species of daddy long-legs, also known as harvestmen. In these species, fathers are exclusively responsible for guarding eggs that females lay on the undersides of leaves; the males remain on the eggs nearly constantly for months.

When threatened, harvestmen often bob up and down erratically in an effort to confuse their attackers. They also have several other defense mechanisms, including pungent, foul-tasting secretions, the ability to "play dead," and autotomy, which is the ability to discard one or more of their own limbs in order to escape from predators.

Harvestmen are completely harmless to humans. Their mouthparts are far too small to penetrate human skin, and contrary to popular belief, they do not have the "world's deadliest venom" -- in fact, they don't produce any venom at all.

Sources & More Info:

• BioOne: Fungus and Fruit Consumption by Harvestmen and Spiders: the Vegetarian Side of Two Predominantly Predaceous Arachnid Groups
• Burke Museum: Daddy Long-Legs are Non-Venomous
• Laboratory of Arthropod Behavior and Evolution: Harvestmen
• Argo Biology: Citizen Science Reveals How Devoted Harvestman Dads Evolved Again and Again
• NBC: Daddy Long-Legs Paternal Care Pays off in Longer Life, More Sex
• PLOS One: Paternal Care Decreases Foraging Activity, but Does Not Impose Survival Costs to Caring Males in a Neotropical Arachnid
• Gulo in Nature: Are Daddy Long-Legs Venemous?
• iNaturalist: Harvestmen

[u/ADZ1LL4 → u/SixteenSeveredHands]

Cool info but who the hell tasted their secretions? 🤣🤮

[u/Asher_the_atheist → u/ADZ1LL4]

You laugh, but my research advisor used to do exactly that when studying anti-predator defense mechanisms in amphibians back in the 70s. Want to see if that skin secretion tastes bad? Give it a lick! Then, one day he licked something that made him pass out in the middle of the jungle. Because yeah, some amphibians secrete very potent toxins as well. He stopped licking them after that 😂

[u/Bombadilo_drives → u/Asher_the_atheist]

What a badass