Archive for the ‘invertebrates’ Category

Autumn Butterflies

September 29, 2022

Temperatures finally dropped here in Augusta, Georgia, making my frequent jogging much easier. A rainy August followed by a dry September must have created good conditions for butterflies because I’ve been seeing a multitude of them during my jogs. At least 3 species flutter about the roadsides in my neighborhood. I already wrote about gulf fritillaries (Agraulis vanilae) a few years ago. (See: ) Giant sulphurs (Phoebis sennae) are big yellow butterflies easy to identify. In their larval caterpillar stage they feed upon legumes such as partridge pea and vetch, both of which are fairly common in my neighborhood.

Adult and larval stages of the giant sulphur butterfly.
Adult and larval stages of the black swallowtail butterfly.
Adult and larval stages of the tiger swallowtail butterfly. The above photo is of the dark phase of this species. Most specimens are yellow with stripes.

The 3rd species I’ve been seeing is either the dark phase of the tiger swallowtail (Pteraurus glaucus) or the eastern black swallowtail (Papilio polyxenes). They won’t stay still long enough, while I’m jogging to identify them, though I’ve positively identified both in my backyard in the past. I suppose I could chase the ones I’ve been seeing during my jogs and catch them with a butterfly net to identify which species is fluttering about, but that is too much trouble. I think they are probably tiger swallowtails which are normally yellow with black stripes and easy to identify, but they do come in a dark phase similar in appearance to black swallowtails. The larval caterpillar stage of the eastern black swallowtail feeds upon plants in the carrot and citrus families. Tiger swallowtail caterpillars feed upon a wide range of plants including foliage of cherry, tulip, and magnolia. Wild black cherry trees are a common component of the local woods. Scientists believe the dark phase of tiger swallowtails mimics the appearance of pipevine swallowtails, a species of butterfly that tastes bad to birds. This mimicry reduces predation. Adult butterflies don’t eat solid food, but get their nutrients from flower nectar, feces, and minerals dissolved in mud puddles.

Trichinella sp.

April 12, 2022

My late father was a physician fresh out of medical school when he encountered a patient with symptoms that baffled his more experienced colleagues. The patient suffered from fever, nausea, diarrhea, fatigue, muscle soreness, headache, stomachache, and eye swelling. None of the older doctors could diagnose his ailment, and the young teenager appeared to be on the verge of death. In desperation they consulted with my father, and he recognized the symptoms of trichinosis, a parasite infection caused by roundworms in the trichinella genus. At first the teenager denied eating undercooked pork, but then he admitted to tasting uncooked pork sausage. He was treated with life-saving anti-parasite medications. The boy’s father happened to be a gangster who worked for the mafia, and after this incident my dad liked to brag the mafia would get him anything he wanted in gratitude. My dad also liked to think his help influenced the boy not to follow in his father’s footsteps. Instead of becoming a gangster, he chose dentistry as his profession.

Lifecycle of a trichinella round worm parasite. Image from the CDC.
Image of trichinella cysts in human muscle tissue. From a medical encyclopedia.

Carnivores, humans, pigs, and rodents spread trichinella worms when they consume meat infested with roundworm cysts. Digestive juices in the small intestine activate the cysts, freeing the roundworms from encasement within the cyst. The parasites pierce the lining of the small intestine and enter the blood stream where they burrow into muscles, mate, and lay eggs that become cysts, waiting to get eaten. How sick an animal gets depends on how many cysts are ingested and how strong the animal’s immune system is. An ingestion of highly infested meat can be fatal because the trichinella worms will also burrow into heart, lungs, brain, and eye tissues. Doctors diagnose trichinosis by taking a muscle biopsy and exposing it to digestive juices. If roundworms are activated, the patient is considered to have trichinosis. Patients are treated with anti-parasite medications including mehendozole or albendozole.

Trichinella is supposedly absent from pork raised in the U.S. and western Europe because modern pigs are fed a clean grain-based diet and are kept in sanitary cages where they don’t have the opportunity to eat dead rats. This hasn’t always been the case. During the middle of the 20th century, trichinella was widespread among domesticated pigs. One study in 1947 of 5000 people found trichinella roundworms in 16.1% of the population. The infestation rate was particularly high in New York City during the 1930s because New Jersey pigs were fed restaurant garbage with trichinella-infested meat and rats. An average of 400 cases of trichinosis were diagnosed every year during the middle of the 20th century, and this figure is likely an undercount because trichinosis symptoms mimic flu symptoms. Many people with trichinosis probably thought they had the flu. As late as the 1960s, 2.2% of Americans had trichinella parasites in their bodies.

New cases of trichinosis in the U.S. average about 20 a year now, and these are from hunters who consume undercooked wild boar or bear. The CDC recommends cooking meat to an internal temperature of 180 degrees F to kill trichinella, though other sources say temperatures as low as 120 degrees F are adequate. Freezing meat at 5 degrees F for 10 days will kill Trichinella spiralis, but freezing does not kill other species of trichinella, and these species are more likely to be found in wild game.

I ate wild boar last week. Sprouts Market sells Durham Ranch products, and this company sources wild boar from Texas. I made wild boar papardelle–a dish reportedly popular in the Tuscan region of Italy. To make wild boar papardelle, marinate 1 lb of ground or finely chopped wild boar in 1 cup of Burgundy and 1 TBL of rosemary overnight. Put a carrot, onion, and chopped garlic in a food processor and grind them up. Remove the meat from the marinade and brown it in an electric skillet, while sautéing the chopped vegetables. Mix the vegetables with the meat and add the marinade and a 6 ounce can of tomato paste. Let this simmer, then add cooked egg noodles. In Tuscany parmesan cheese is not added, but my wife and daughter wanted it on their servings. The meat tastes of wine and tomato paste, and any meat would probably taste the same with this recipe.

Wild boar should be cooked thoroughly. Unlike pigs raised in modern sanitary conditions, wild boar can ingest trichinella parasites.
Wild boar papardelle is reportedly a popular dish in the Tuscany region of Italy. It’s easy to make.

Golden Silk Orb Weavers (Trichonophila clavipes) in My Yard

September 17, 2021

Golden silk orb weavers made my backyard their home this summer since about the middle of June. Last week, I counted 5 different webs in my yard. Their webs are huge, measuring 10 feet across and 6 feet from top to bottom. These deadly traps catch all kinds of insects from mosquitoes to wasps. This species is not reported to prey upon vertebrates, but I would not be surprised, if they do catch tree frogs, hummingbirds, and bats on occasion. They are a large spider over 1 inch long from abdomen to head, and their leg span is even wider. Golden silk orb weavers are also known as banana spiders because most are yellow. (They are also some times found in boxes of bananas.) The specimens in my yard seem to be brown with yellow spots, likely a local variation. This species ranges from North Carolina to Argentina, and they are expanding their range due to global warming.

There are currently at least 5 golden silk orb weaver webs in my backyard. The webs measure about 10 feet across and about 6 feet from top to bottom. They angle their bodies according to the time of day to reduce direct exposure to the sun. The webs survived a recent rain storm from the latest hurricane. I took this photo.

Golden silk orb weavers belong to the Nephilidae family and were formerly given the scientific name Nephila clavipes. However a recent genetic study determined they should be classified in the Trichonophela genus within the Nephilidae family. Females are 6 times larger than males, so if a smaller spider is seen in their web, it is probably a male. Females eat males when they are done mating with them. A genetic study suggests the characteristic of female gigantism in the Nephilidae family originated over 100 million years ago. There is another species of spider–the silver-colored, fat-bodied Argyrodes nephilae–that some times lives on the outside of golden silk orb weaver webs. This species steals captured prey from the golden silk orb weaver by cutting the webbing attached to the web-wrapped insect and lowering it to the outside of the golden orb weaver’s web where it is safe for the Argyrode spider to consume. A golden silk orb weaver web is an ecological community in itself with female and male golden orb weavers, web-wrapped insects, and a smaller species of spider that lives life as a thief.


Kuntner, M. et. al.

“Golden Orb Weavers Ignore Biological Rules: Phylogenomic and Comparative Analysis Unravel a Complex Evolution of Sexual Size Dimorphism”

Systematic Biology 68 (4) July 2019

Monster Centipedes

September 10, 2021

The top predator on Philip Island is a 12 inch long centipede with armored plating and a venomous bite. This monstrous creature preys upon sea bird nestlings, lizards (skinks and geckos), and crickets. It also eats the vomited fish and squid parent birds regurgitated to feed their chicks. About half of its diet consists of vertebrates, an unusual ratio for a terrestrial invertebrate. Scientists estimate 11%-19% of black-winged petrel chicks are lost to centipede predation every year. However, centipedes don’t prey upon white winged petrel nestlings because they are larger and can defend themselves against the centipedes.

Phillip Island Centipede with a black-winged petrel. This species of centipede regularly feeds upon black-winged petrel chicks. 13 species of sea birds nest on Philip Island. Photo from the below referenced study.
Photo and location of Philip Island. Note how denuded the island is of vegetation. This is from feral pigs, goats, and rabbits all of which have been eradicated. Image also from the below referenced study.

Scientists think centipedes may be able to help restore the ecology of Philip Island. Originally, the island was covered with white oaks, Norfolk pines, and red legged grass; but sailors introduced goats, pigs, and rabbits as a food source, and the feral animals denuded much of the island of vegetation. People eradicated the animals about 40 years ago to save the island ecosystem. Centipedes eat the sea birds and transfer marine nutrients to the rest of the island in their feces. This added nutrition may help the trees and grass grow back faster.

This is the largest species of centipede that lives in Georgia. Scolocryptis sexspinosus. It grows to 3 inches long. I’ve seen this species in my yard. Photo from

The largest species of centipede in Georgia grows to about 3 inches long–1/4th the size of the Philip Island centipede. This species is known as the red bark centipede (Scolocryptis sexspinosus), and I have seen this species in my yard. They have a venomous bite that is painful to humans but not fatal. It can live up to 5 years and will molt its exoskeleton as it grows. They are predatory but not often seen because they are usually nocturnal and fossorial. Worldwide, there are 8000 species of centipedes. Though their name means 100-legged, their number of legs can vary from 54-354, depending upon the species. Centipedes don’t mate. Instead, the male drops off its sperm, and the female later comes along and engulfs it. Females defend their eggs, and some species even defend their young.


Halpin, L; et. al.

“Arthropod Predation of Vertebrate Structures Trophic Dynamics in an Island Ecosystem”

The American Naturalist 198 (3) September 2021

Fossorial Spiders in Georgia

July 2, 2021

2 different groups of spiders live underground in Georgia soils: trapdoor spiders and wolf spiders. Trapdoor spiders belong to the Myglamorph order which also includes tarantulas, funnel web spiders, and purse web spiders. (The latter make tube shaped webs on tree trunks.) In Georgia there are 3 families of trapdoor spiders including the Ctenizidae (ravine trapdoor spiders), the Antrodiactidae (folding door spiders), and the Eucterizidae (wafer lid spiders). Spiders in the Ummidia genus belong to the Ctenizidae family, and as their name would suggest, their preferred habitat is moist ravines located next to rivers. However, most species of trapdoor spiders seem to prefer this type of environment. 1 recent study searched for trapdoor spiders in moist ravines along the Altamaha, Savannah, and Satilla Rivers in Georgia, and the spider hunters found 51 specimens including 3 species. Along with 1 species of ravine trapdoor spider, they also found wafer lid and folding door spiders.

All trapdoor spiders construct underground burrows where they wait for prey to cross across the door. When the spider senses an insect on its door, it will seize the unfortunate prey with fangs and pull it inside the burrow where the spider feeds upon it. The families differ in how their doors are constructed. Ummidia spiders use their abdomen covered in webbing as a door. Folding door spiders pull the rims of their burrows closed, unfolding it in time to catch an insect. Wafer lid spiders have a thinly-webbed door. Incredibly, the wafer lid spider, Myrmekiaphilia, constructs its burrows inside or alongside ant nests. Some species of wasps hunt trapdoor spiders. The arachnids have a defense–they desperately attempt to hold the door shut while the wasp tries to pull it open. Somehow, they are able to tell the difference between prey and a wasp.

There are at least 8-10 known species of trapdoor spiders in Georgia. Auburn University professor, Jason Bond, has discovered 37 species of trapdoor spiders in North America, and there likely are more than 10 species living in Georgia with many undiscovered. He’s named newly discovered spiders after celebrities including Barack Obama, Tobey Maguire, Angelina Jolie, and Stephen Colbert.

The moist mesophytic slopes where trapdoor spiders occur are particularly rich habitats for all wildlife. William Bartram described walking through a “magnificent” slope forest in his Travels. (See: ). A forest such as Bartram described no longer exists in Georgia, but even logged over 2nd growth forests are richer on these sites because they are wetter and cooler than the surrounding habitats. During Ice Ages when much of the surrounding environment was dry scrub, these sites likely provided refuge for hardwood forests and hence relic habitat for trapdoor spiders.

This photo angle is not good enough to identify what species of spider this is in my rain gauge, but I can tell it is not a trapdoor spider as I wrongly assumed at first. I made this false assumption because I thought a trapdoor spider was using an existing structure that imitated its burrow, but that is not the case.
Photo of a ravine trap door spider in the Ummidia genus. Photo from
Wolf spider from the Tigerosa genus. This is the kind of spiders I see when I dig in my garden. Photo from

I often come across spiders when I dig in my garden. Until I started researching information for this blog article, I wrongly assumed they were trapdoor spiders. Instead, I learned these are wolf spiders, probably belonging to the Tigrosa genus (named for the striped appearance). Wolf spiders are in the Lycosidae family, and they also construct burrows underground. Unlike trapdoor spiders, they are not sedentary predators. They hide from predatory birds in their burrows during the day, but they leave their burrows at night and actively hunt insects. They probably attack crickets, homing in on their noisy chirping. A wolf spider’s burrow can be as deep as 3 feet, keeping them safe from inclement weather and birds, but moles can find them. Female wolf spiders carry their eggs and young on their backs when they hunt at night. They are far more common than trapdoor spiders, and worldwide there might be as many as 2000 species.


Stevenson, D.; and R. Godwin

“Notable Myglamorph Spiders (Aranae: Myglamorphae) Records for the Coastal Plain of Georgia”

Southeastern Naturalist 19 2020

Pleistocene Ant Lions (Myrmeleontadae sp.)

April 29, 2021

Ant lion pits line the bare soil areas next to the back wall of my house. Ant lions, as the name suggests, prey on ants, though they will eat anything small enough to become trapped in their pits. The larval stage of most species is the monster hidden just below the sand of the bottom of the pit. When an ant lion larva senses an ant walking near the edge of the pit, it flicks sand at the ant, knocking the ant into the side of the pit. The action of flicking sand destabilizes the wall of the pit, forcing the ant to fall within the reach of the ant lion’s jaws. The ant lion then injects venom and devours the ant, or rather sucks the juices out of it. Ant lion larva can live for years without eating and during winter they dig deeper down to avoid frosts. But after they’ve had a meal, they go into a cocoon stage before emerging as adults. They survive on nectar for energy in their brief adult stage spent searching for mates. Fertilized females lay eggs in sand and the cycle begins again.

Some species of flies lay their eggs in abandoned ant lion pits, and their larva use the same strategy as ant lion larva. At least 1 species of parasitic wasp allows itself to be captured. It stings the ant lion larva and lays on egg on it, thus turning predator into prey.

Ant lion adult and larva. Image from below reference. The larva prey on ants and other small arthropods.
Ant lion pits next to the side of my house. Ant lions prefer sandy soil and are common in arid environments. They likely were abundant in the southeast during Ice Ages when the climate was dry and bare soil environments predominated.

There are about 2000 species of ant lions, and there are species on every continent except Antarctica. Their closest living relatives are owl flies and lace wings. They are most common in tropical dry climates, but they thrive anywhere they can find a sandy substrate. I hypothesize they were abundant in southeastern North America during Ice Ages when arid climates prevailed, resulting in vast landscapes with sparse vegetation. Pleistocene climate changes likely increased species diversification when populations became isolated from each other during wetter climate phases that turned sandy environments into isolated refuges.

Ant lions are rare in the fossil record. Ant Lions have been found in 99 million year old amber at a site located in Burma. Scientists think ant lions first evolved about 150 million years ago, so they lived under the feet of dinosaurs. There are no dinosaurs in my yard (unless one includes birds), but their contemporaries live right up next to my house.


Badano, D.; M. Engel, P. Basso, B. Wang, P. Cerretti

“Diverse Cretaceous Larvae Reveal the Evolutionary and Behavioral History of Ant Lions and Lace Wings”

Nature Communications (9) 257 August 2018

North American Army Ants

June 17, 2020

Most people are familiar with the army ants of South America and the driver ants of Africa featured in many nature documentaries, but few are aware army ants also occur in North America.  There are 30 species of army ants from the Neivamyrmex genus and 1 species from the Novamyrmex genus living on this continent.  North American army ants differ from those of South America and Africa.  North American army ants cross the landscape in more narrow spear-headed swarms than those of their tropical cousins.  Nevertheless, they are just as predatory.

Neivamyrmex nigrescens, Arizona

A species of North American army ant.  Notice how thick their antenna are. Years ago, I witnessed army ants tearing apart an earthworm in Columbia County, Georgia. This photo is by Alex Wild from the below link.

Army ants don’t live in permanent nests.  Instead, they alternate between foraging and stationary phases.  During foraging phases they roam across the land searching for food to feed their larva.  They mostly eat other ants and are built to subdue other species.  They have muscular bodies and thick antennas that other ants can’t bite through.  When the larva go into the pupa stage, army ants enter the stationary phase and live within a swarm of their own bodies.  Colonies produce new queens every 3 years, and the colony will split into 2 after the new queen is born.  Most army ant colonies perish when the queen dies, but some manage to track down a closely related queen and will merge with that colony.

There are over 200 species of army ants worldwide including 5 genera in the Americas and 2 genera in Africa and Asia.  A study of army ant genetics determined some genera of American army ants are closely related to African army ants.  They diverged 100 million years ago before Africa and South America drifted apart.  Other genera of army ants are not closely related to other army ants and are examples of convergent evolution.


Range map of army ants in North America.  Map is also from the below reference.

Cold climate apparently is a limiting factor for army ant distribution, but it might not be the temperatures.  I noticed in the map of their distribution that the northern limits of their range approximately corresponds to the southern limit of Ice Age glaciers.  Like many species of trees, they simply have been unable to colonize deglaciated territory even though they can survive the cold temperatures of Iowa and Nebraska.


Most of the information for this blog entry comes from Alex Wild, a Texas entomologist.  This links to his website.

Bald Faced Hornets (Dolichovespula maculata) are Marvelous Engineers

October 5, 2019

Humans were not the first species to manufacture paper.  Wasps were building paper nests millions of years before  Homo sapiens  evolved.  The bald faced hornet builds the largest, most spectacular nest of any species of wasp, and I always love finding these in the woods.

Bald Faced Hornet

Bald faced hornet’s nest.

A mature bald faced hornet’s nest holds 400-700 workers.  A pregnant queen emerges during spring and begins building the nest but she is soon aided by workers she births. The hornets make the paper by chewing wood.  The workers are all sterile females, and sterile males also live in the nest.  Meanwhile, the queen keeps laying eggs.  By late fall these eggs become future queens and drones (fertile males).  The queens and drones leave the nest, and the latter impregnates the former.  The pregnant queens than overwinter under cover to emerge the following spring.  Bald faced hornets are carnivorous, feeding upon soft-bodied invertebrates and carrion.  They attack caterpillars, fly larva, and spiders that they then feed to their larva.  The adults get their energy from flower nectar and fruit.  People picking fruit need to be careful not to pick up a piece of fruit being enjoyed by a bald faced hornet.  They love my scuppernong grapes.  Plums are another favorite.

The bald faced hornet is not a true hornet but rather a yellow jacket wasp.  All hornets are wasps, but only some species of wasps are hornets.  Hornets are generally larger in size and less colorful than other species of wasps.  Hornets build paper nests, while most wasps build nests suspended in the air, on the ground, or underground.  But to add to the confusion, bald faced hornets do build paper nests though they are not true hornets.  The difference between true hornets and wasps involves technical anatomical differences that I am not going to cover here.

Bald faced hornet.

Bald faced hornets are widespread and adaptable.  This species expanded throughout deglaciated Canada in less than 10,000 years following the last Ice Age.

Bald faced hornet range map.  Note how they occur in the geographic region that used to be covered by glacial ice.  They’ve colonized territory all the way to central Alaska.  Amazing.

As far as I can determine, there is no Pleistocene-aged fossil evidence of bald faced hornets or their nests.  Insects are rarely preserved, and of course paper nests deteriorate rapidly when exposed to the elements.  I’m sure they were just as common during the Pleistocene as they are today.

Pleistocene Squid

February 11, 2018

The cephalopods were the most intelligent creatures on earth for hundreds of millions of years.  Nectocurus pteryx, a squid-like ancestor of all cephalopods, lived 500 million years ago during the Cambrian Age.  Fossil specimens of this species are found in the famous Burgess Shales.  Cephalopods–a group that includes squid, octopus, cuttlefish, nautiloids, and the extinct ammonites–evolved arms they can use to manipulate objects, and squid, through convergent evolution, evolved eyes quite similar to the human eye, so they can see the world like we do.  This explains how they evolved intelligence much greater than that of other invertebrates.

This blog article, like my entry about Pleistocene spiders, is entirely speculative because cephalopods have soft bodies that are also rarely preserved.  During Ice Ages sea levels receded and dry land extended across the continental shelf, today inundated by ocean water.  It seems likely deep water species of squid inhabited waters adjacent to the shore because steep drop-offs existed much closer to land during these climatic stages.  Giant squid (Architeuthis dux), reaching lengths of 43 feet, and colossal squid (Mesonychoteuthis hamiltoni), almost as long, probably lurked near the coast, whereas today they are normally restricted to deeper waters far out to sea.

The Gulf Stream current that keeps land temperatures moderate in the northern hemisphere often shut down or was greatly reduced during episodes of glacial meltwater influxes known as Heinrich Events.  These must have had an impact on squid migration.  Many species of squid migrate long distances to spawning grounds, and Heinrich Events must have altered their paths of movement, species abundance, and species composition.  Large die-offs probably occurred in some species, while others may have benefitted from the chaos.

Squid are an important food source for marine mammals, and deep sea species of whales likely ventured closer to shore in search of squid during Ice Ages.  Seals then living on the shores of the Atlantic Coastal Plain fed on squid.

The composition and species abundance of squid during various stages of the Pleistocene will forever remain a mystery.  There are over 300 known species of squid in the world today, but scientists know little about squid species abundance of the present day, let alone of the distant past.  One study of squid off the eastern coast of Florida determined eye flash squid (Abralia cf veranyi), flying squid (Ommastrephidae sp.), and shortfin squid (Illex sp.) were the 3 most abundant genera or families.

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Eye flash squid are 1 of the most common species found off the coast of eastern Florida.

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Shortfin squid–another common species.

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Flying squid shoot out of the water to escape predators.  


Sperm whales feed mostly on squid.  Individuals can be distinguished by scars from battles with giant squid.

I’m not impressed with the flavor of calamari.  I’ve had it in a Vietnamese pho soup.  The soup itself was delicious, but the calamari was rubbery and tasteless.  I’ve tried fried calamari but this too had no flavor.  The best squid I’ve ever eaten was a canned Korean product.  The squid, packed like sardines, were seasoned with soy sauce and sugar.  The seasoning would’ve made anything taste good.  However, the squid were not cleaned, and I had to be careful chewing so I wouldn’t break a tooth on the hard beaks.


Erickson, Carrie; Clyde Roper and Michael Vecchione

“Variability of Paralarval-Squid Occurrence in Meter-net Tows from East of Florida, USA”

Southeastern Naturalist 16 (4) 2017


Spider Romance or How to Eat your Mate

October 25, 2017

Halloween decorations often include mock spider webs  because many people think of spiders as creepy.  I don’t.  I think they are fascinating.  There are over 44,000 known species of spiders in the world with about 400 new species named every year.  Most spiders trap their prey in the sticky substance produced in their abdomen, then they quickly pounce on the struggling insect and inject a paralyzing venom that liquefies the insides.  After their prey is subdued the spider sucks the juices from the helpless victim.  I suppose that is an horrifying fate for insects, but people have nothing to fear from such a small organism so vulnerable to a rolled up newspaper.  (I never kill spiders.  Instead, I catch and release them, if they invade my house.)  The spider’s strategy of trapping prey in a web poses a dilemma for males seeking a mate.  It is difficult for a female spider to discern the difference between food and potential sex.  Male spiders must tap on the web in a certain way, communicating to the female they are a sperm donor, not a trapped fly. Mistakes are occasionally made.

Female spiders are larger than male spiders, but in some genera sexual dimorphism is extreme.  Evolution has led to female gigantism among orb-weaving spiders.  Nature has selected for large females and small males in orb-weavers for 4 reasons: a) large females are more fertile and produce more eggs, b) larger females are less likely to fall prey to predators, c) small males reach sexual maturity at an earlier age, and d) small males are better climbers and can reach females faster than others when journeying up the web.  If after sex, a female spider eats a male, there is no great loss.  The female has already been fertilized, and the male is more useful as extra nutrition.  This reproductive strategy is not satisfactory for lampshade spiders.  Female lampshade spiders have larger bodies than males, but the males do have longer legs.  This gives male lampshade spiders the ability to escape after mating, so they can impregnate other females.

Image result for large female spider, small male spider

Female and male banana spiders (Nephilia clavipes).  Evolution has selected for large females and small males in spiders.  

Lampshade spiders construct webs in the shape of a lampshade, hence the name.  Females are larger than males in this species as well, but the males have longer legs, so they can escape after mating.

Humans are not as different from spiders as one might think, especially considering risky sex.  People aware of sexually transmitted diseases, including deadly AIDS, are still often willing to have unprotected sex with strangers.  Men and women cheat on their significant others, even though they realize their jealous partner might shoot or stab them, if their indiscretion is discovered.  And some people, mostly men, pay dominatrixes to bind them, putting them in a situation not dissimilar from male orb-weaver spiders.

Many men are attracted to woman who are larger than they are.  My personal preference is for women with really large breasts and buttocks, and I don’t mind if a woman is heavier than I am.  But some men have a fetish for extremely large women…in fact unrealistically giant women, known as giantesses.  They fantasize about a woman who can hold them in the palm of their hand.  The desire male spiders have for gigantic female spiders evidently exists in some human males as well.  Though psychological triggers in the environment probably influence this fetish, there must be something deep inside the mating urge, providing the platform for it to develop in people.  This template is something we share with spiders and likely goes back to a common ancestor over 500 million years ago.

Image result for giantess fetish

Many men are turned on by women who are much larger than they are.  Some even fantasize about giantesses.

The association of sexual excitement with fear of being eaten is another characteristic some humans share with spiders and other creatures.  I’m 55 years old, and I thought I was aware of every sexual fetish, but I first learned about the vore fetish within the last year.  Vore is short for devour–some people are sexually excited by the thought of being eaten by their sexual partner.  I don’t really understand this fantasy.  How, for example, does one reach sexual satisfaction after they’ve been eaten?  I think maybe this fantasy has something to do with being in the warm amniotic sac of a woman’s tummy.  Or maybe some are really thrilled with the thought sex might lead to their consumption.  Nevertheless, deep down inside, humans are like spiders in more ways than we would like to admit.

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People are not as different from spiders as one might think.  Some people get sexually excited at the thought of being eaten by their mate.  It’s known as a vore fetish.


Kuntac, Matjaz; Jonathan Coddington

“Discovery of the Largest Orb-Weaving Spider Species: The Evolution of Gigantism in Nephilia”

Plos 1  October 2009