Sexual Suicide

Wayne's WordIndexNoteworthy PlantsTriviaLemnaceaeBiology 101BotanySearch

Volume 7 (Number 1) Spring 1998
Sexual Suicide
"Self-Destructive" Behavior in Males Of Some Animals
© W.P. Armstrong 15 April 2009
This issue of WAYNE'S WORD is dedicated to all those brave males who literally gave their lives
to the female of their species during (or shortly after) copulation (i.e. sexual intercourse).   From
an evolutionary perspective, the old adage, "It is better to have loved and lost than never to have
loved at all," should now say "It is better to have loved and died than never to have loved at all."
Disclaimer: The subject of this article is complex and controversial. Although it includes anthropomorphic
metaphors and double-entendre sexual innuendos, it is based on scientific "peer-reviewed" studies. It is
not meant to discourage any male from pursuing a meaningful relationship with a female of his species.

  1. Introduction
  2. The Australian Redback Spider
  3. The Praying Mantis Controversy
  4. The Sad Saga Of The Drone Bee
  5. Mysterious Males Of Deep-Sea Angler Fish
  6. The Incredible Fig/Fig Wasp Scenario
  7. The Sexual Suicide Crossword Puzzle
  8. Answers To Sexual Suicide Crossword Puzzle      

Introduction

Several years ago, while walking across a parking lot on the Palomar College campus, I noticed a dead honey bee lying on its back. The bee was clearly larger than a typical worker bee, and had an elongate, cylindrical organ mass projecting from the tip of its abdomen. A botany student (and part time apiarist Alan Tiso) suspected that the bee was a male honey bee (called a drone) because of its larger body size, lack of pollen-collecting baskets on its legs, and the phallus-like cylindrical projection from its rear end (which lacked the painful, needle-like stinger of typical worker bees that we have all experienced all too often). Later we discovered that this unfortunate individual was indeed a male honey bee and the cylindrical projection was his penis apparatus (technically referred to as an endophallus), undoubtedly extended during his fatal mating flight with a queen. Our deduction seemed tenable considering that a large apiary occurred at the nearby summit of Owens Peak, just northeast of the campus. This grim discovery eventually evolved into a series of general biology lecture notes about the plight of males, and finally into this historic piece of cyberspace.

Sexual intercourse is the ultimate bond between a male and a female, but for some hapless males it is also their demise. We are not referring here to financial demise (in the case of some unfortunate male humans), but rather, the abrupt and untimely termination of the male's life. Not only does the male sacrifice his life for the female, but she often dines on his lifeless body after the sex act. In many other species, the males are not actually killed by the female, but their lives are reduced almost solely for sex, after which they are genetically programmed to self-destruct. These males have little or no social interaction with females, and are merely sperm providers, or in molecular terms, "DNA donors."

The staff at WAYNE'S WORD has subdivided these unfortunate males into two main categories based upon the reduction of their bodies and life functions, and whether or not they are eaten by their mate:

A. Sexual Suicide.

Males with normal, functional bodies (usually smaller than the females) and normal life experiences similar to those of the female--until that fateful day when they have a lethal sexual encounter with the female. [I.e. They not only die during or soon after intercourse, but their mate often dines on their lifeless body.]

B. Male Gender Inequity and Exploitation.

Males with greatly reduced body size and anatomy, and with limited life experiences compared with the female--often dying within hours after intercourse or persisting as a tiny blood-sucking parasite attached to the female's body. [I.e. their sole purpose in life is to service or inseminate their mate.]


A. Sexual Suicide


1. The Australian Redback Spider

Probably the most notorious example of "sexual suicide" is the encounter between a male and a female black widow spider (Latrodectus mactans), where the remains of the hapless male suitor often hangs like a trophy in the female's web. This cannibalistic behavior of eating the male during or after sexual intercourse also occurs in other closely related species in the family Theridiidae, including the infamous Australian redback spider (L. hasselti). The remarkable courtship behavior of the redback spider has been studied extensively by Maydianne C.B. Andrade at Cornell University in Ithaca, New York. (Science Vol. 271, 5 Jan. 1996). Although some researchers have argued that the males are eaten because they simply aren't "lucky" or "smart" enough to escape from their mate's clutches, Ms. Andrade has demonstrated an entirely different scenario for the redback spider. In fact, the redback actively seeks his own doom, positioning himself above the female's jaws (chelicerae) during copulation so that he can readily be devoured by the female. Although the female may outweigh her male suitor by more than 5,000 percent, there are times when his feeble body is not consumed. [This noticeable difference in the size and anatomy between males and females of a species is called sexual dimorphism.] In related species there are even documented cases where the male actually escapes from the massive female and her web of death, and may even mate again with another female.

Australian redback spider (Latrodectus hasselti) photographed by Stephanie Mifflin.

According to Ms. Andrade, the female redback's habit of slowly eating her mate during copulation may have several important survival functions by:

(1) Prolonging intercourse, thus making it more likely that his sperm will fertilize her eggs.

(2) Dampening the females passion, thus making her less likely to mate with another male.

(3) Sacrificing the males body, thus providing a nutritional supplement helping to insure a larger batch of eggs.

This selfless, non-traditional sexual role of the male redback spider gives new meaning to the phrase "A Love To Die For."

A female black widow spider (Latrodectus mactans) guarding her egg case. Her deceased hapless mate (his remains seen in lower right) provided her with sperm and a quick meal. [Illustration by graphic artist Elaine M. Collins.]

The black widow (Latrodectus mactans = L. hesperus) is one of the most poisonous spiders in North America. The neurotoxic protein latrotoxin is produced in glands of the cephalothorax and is injected through hollow fangs (chelicerae). Although the mechanism is very complex, alpha-latrotoxin apparently interferes with the normal flow of calcium ions across nerve cell membranes, thus effecting muscular contractions. Latrotoxin is an activator of synaptosomal calcium uptake, while conotoxin from the cone snail (Conus) is an inhibitor of calcium channels, yet both deadly toxins ultimately produce cramping or rigid paralysis. Latrotoxin is more toxic than most snake bites with a lethal dosage (LD-50) of 0.9 mg/kg in mice. [LD-50 is the dosage required to kill 50% of the experimental animals.] If you live in southern California, there is probably one of these spiders near or under your house at this very moment. Chilean scientists have been researching latrotoxin as a treatment for erectile dysfunction coupled with temporary infertility (contraseption).

Cone snails of the genus Conus, including the South Pacific C. geographus, can inject a potent neurotoxin (called conotoxin) that belongs to a class of poisons called calcium channel blockers. These toxins inhibit the flow of calcium ions into cardiac (heart) and smooth muscle cells. A sufficient inflow of calcium ions is necessary for contraction of the heart muscle. Muscle contraction involves the reaction of actin and myosin microfilaments which slide over each other. Calcium is essential for the phosphorylation of myosin; an insufficient uptake of calcium ions can result in cardiac arrest. As a medical treatment, calcium channel blockers are used to lower blood pressure, relieve painful angina, and to stabilize abnormal (irregular) heart rhythms.

See: Affect Of Poisons On Nerve Tissue


2. The Praying Mantis Controversy

A female mantis finishing off the remains of her hapless male suitor following his suicidal sexual encounter. The details of this unfortunate male's death (and why his death will not be in vain) is explained in the following two paragraphs.

Although there is some disagreement among authorities, sexual encounters between praying mantids often result in a horrifying experience for the hapless male. Praying mantids are well-adapted for capturing and demolishing prey with strong, grasping (raptorial) forelegs, powerful jaws (mandibles), and a triangular head and large eyes resembling an alien creature from "The X-Files." Mantids spend all summer preying upon all sorts of insects and spiders, periodically molting their exoskeleton and enlarging their bodies. After about two weeks following his final molt, the male mantis reaches sexual maturity and begins to seek out a female. Like other males (including humans) he is driven by genetic programming and an irresistible scent secreted by the female. [Human males are also driven by high levels of testosterone, often not thinking with the head on their shoulders.] Experimenting with European mantids, K.D. Roeder of Tufts University in Medford, Massachusetts, has made some startling observations on the brutal sexual behavior of these remarkable insects. Since the male is smaller than the female, he can be overpowered by her rather easily. Therefore, he must approach her very cautiously and slowly, preferably while she is busy grooming herself or catching and feeding upon another insect victim. If he approaches her carelessly (like in a Peter Sellers comedy), he very likely will never live to pass on his genes. If his approach is successful he mounts her back, tightly clasping her with his forelegs and penetrating her ovipositor with his penis apparatus. [The explicit, x-rated details of this act is beyond the scope of this article and may result in the expulsion of WAYNE'S WORD from the Palomar College web site.] Occasionally the female is not receptive to the male's advances, and quickly turns on him--biting off his head. Curiously enough, a reflex mechanism in the male allows him to complete the mating process without his head. [Mindless mating without using one's "thinking head" is also a common phenomenon in many human males.]

After mating, the intact male (assuming that he didn't lose his head) often shows little or no inclination to escape from his savage mate. Although some males do escape unscathed, many are seized by the female and are dismantled and eaten organ-by-organ, often head first. Serving as a "last supper," the sacrificial male provides his mate with a meal in late autumn when insect food supplies may be scarce, and when she desperately needs vital time and energy to make several egg cases packed with hundreds of eggs. Like the black widow spider, the male mantid's sexual suicide is certainly not in vain.

Although it is difficult to top the sexual suicide behavior of male redback spiders and mantids, another remarkable example of this male self-destruction and cannibalism is worth mentioning. It concerns female fireflies of the genus Photuris, members of the beetle family Lampyridae. Like other members of this large beetle family, they have bioluminsecent organs at the tip of their abdomen which they use to attract members of the opposite sex. Different species can identify their own kind in the darkness of night by the peculiar flash pattern for their species, which is based on the length of the flashes and the precise time interval between flashes. The animal behaviorist James Lloyd (Science Vol. 149, 1965) described the female photuris beetle as the ultimate "femme fatale" of the insect world. She uses the light at the tip of her abdomen to signal males of her own species and to mimic the flash patterns of unsuspecting males in the related genus Photinus. Attracted by her seductive blinking lights that mimic their own females, the photinus males attempt to mate with her, but soon become victims of lust as their bodies are devoured by the cannibalistic photuris female. In the following example, the hapless male is not eaten by his mate, but nonetheless his lust and copulatory behavior will cost him his life.


3. The Sad Saga Of The Drone Bee

The plight of the male honey bee is one of the classic examples of sexual suicide. This incredible story is actually very complex and is eloquently explained by Mark Winston in his fascinating book The Biology of the Honey Bee (Harvard University Press, 1987). Honey bees are social insects that live in complex colonies. They have a division of labor with a true caste system in which different bees assume various roles within the colony. In fact, the way that all the thousands of individuals selflessly serve the collective is somewhat reminiscent of "The Borg" in Star Trek: The Next Generation. Compared with the smaller diploid female workers, the haploid drones have a relatively easy life--until that fateful day when they must fly into the sky for their rendezvous with a sexually receptive queen. The entire sex act takes place during flight, like a jet fighter refueling in mid air. Only in the case of honey bees, the actual bridge between the drone and the queen is his extended penis apparatus (endophallus) which is tightly plugged into the sting chamber of the receptive female. His explosive ejaculation ruptures his everted penis apparatus and propels semen into the queen's oviduct. In addition to the forceful ejaculation of semen, the terminal bulb at the tip of the everted endophallus remains in the queens vagina, and according to Mark Winston (1987), this "plug" may function to prevent semen from flowing out of the vagina following copulation. [So there is truth in the old tale about the drone's penis breaking off inside the female.] In the sci-fi film "Zzzzz" (a TV episode from the 1964 Outer Limits series), a queen bee metamorphosed into a women named Regina. In this "B" rated-film, Regina wanted to mate with the entomologist Ben Fields to produce a super race of bees. It is now very clear why the terrified entomologist/bee keeper did not want to have sex with this queen bee lady. Getting back to the world of real honey bees, the drone bee dies within minutes after his violent eruption of semen and literally falls from the sky, occasionally landing in a Palomar College parking lot. Please refer back to paragraph 1 of Introduction.

A deceased drone honey bee shortly after his fatal mating flight with a queen. The large, cylindrical structure protruding from his abdomen is his everted endophallus, which he used to pump sperm into the queen. This poor chap lying on his back was the primary impetus behind this article.

With her sperm receptacle (called a spermatheca) filled, the queen can lay fertilized, diploid eggs (which become females) and unfertilized (haploid) eggs (which become males) in the hexagonal wax cells of her hive, in one of nature's truly amazing insect cycles. In case you are wondering, worker bees build unfertilized hexagonal cells a little larger in order to accommodate the drone. When full, the queen's spermatheca may contain more than five million sperm, more than enough to lay 1500 fertilized eggs daily during the summer, and up to 200,000 fertilized eggs annually during her life span of nearly four years. According to Mark Winston (1987), the queen may get a complete fill-up of sperm on one mating flight (often from more than one male), or she may make several flights over a period of several days to a week. And during the mating flight of one queen, up to 17 male drones may commit sexual suicide.

In a PBS TV broadcast about honey bees, the narrator referred to drone bees as "clones" of each other. Since clones are usually defined as genetically identical individuals (usually derived asexually), WAYNE'S WORD strongly disagrees with the accuracy of this broadcast. Although the haploid drone comes from an unfertilized egg with only one set of chromosomes, they are certainly not all genetically identical. The diploid queen bee undergoes normal meiosis (oögenesis) producing haploid eggs. During this cell division process her 16 pairs of homologous chromosomes become altered and reshuffled through crossing over and random assortment, resulting in haploid eggs that are not chromosomally identical. In fact, with 16 pairs of homologous chromosomes, there are 65,536 different chromosomal combinations possible. Furthermore, the additional random combination of gametes during fertilization also insures that worker bees are not chromosomally identical. One more gee whiz comment about honey bees. Since the foraging bees bring nectar back to the hive in special stomachs (where it is converted into honey and regurgitated into wax cells of their hive), honey is truly analogous to bee vomit.