Friday 5: Fun Facts About Giant Water Bugs

This week’s Friday 5 features a subject near and dear to my heart: giant water bugs!  If you aren’t familiar with these beasts, they have some really amazing characteristics that make them a fascinating group of insects to study.  I’ve already covered giant water bug parental care and feeding in other posts.  Today I’m going to share 5 fun facts about giant water bugs.  I hope that knowing these facts will help you fall in love with these wonderful bugs!

Lethocerus medius

Lethocerus medius, the biggest giant water bug in Arizona, can reach lengths of nearly 2.5 inches!

1.  The largest true bug (i.e. member of the insect order Hemiptera) in the world is a giant water bug.

Lethocerus maximus is truly a giant, reaching nearly 5 inches in length!  However, if you want to add one to your collection, you’ll have to visit northern South America.  The Lethocerus in the US are piddly in comparison, topping out at about 2.5 inches – half the size of the biggest species.

Abedus cannibalizing eggs

A male Abedus herberti cannibalizing his own offspring after he scraped them off his back.

2.  Giant water bugs can be cannibalistic.

A hungry giant water bug will eat almost anything it can get its claws on, including its own young (only when very hungry or something has gone wrong with the eggs a male is caring for), the young of other individuals, and each other.  Female Lethocerus are also known to rip apart the egg clutches deposited by other females when there aren’t enough males with good egg laying sites to go round.  However, I haven’t observed giant water bugs eating each other in the field unless there is very little other food available and they are getting desperate.  It would seem they prefer not to eat each other, but they will when they have no other choice.

Abedus herberti mating

Abedus herberti mating.

3.  Giant water bug mating can take several hours, especially in the back brooding species.

Mating is a long, involved process in the back brooding giant water bugs.  First the male does little push ups in the water.  These are thought to send vibrations through the water that the females respond to.  After a male and a female find one another, they mate.  Then the female climbs on the back of the male and lays a few eggs, maybe 4.  Then the male shakes her off and they mate again.  Then she lays a few more eggs before being shaken off again.  This goes on and on until most of the back of the male is covered with eggs, sometimes 150 altogether!  You can see how this might take a long time.  The water bugs in the photo took over 6 hours to lay all of their eggs.

Belostoma micantulum

Belostoma micantulum, a giant water bug from Argentina, is one of the smallest giant water bugs in the world.

4.  Not all giant water bugs are giant.

Belostoma parvum, a giant water bug from northern South America, can be less than a centimeter long.  It’s a not-so-giant water bug!  In fact, several species of giant water bugs in the genus Belostoma are actually quite small and don’t live up to the “giant” in their name at all.  The giant water bug pictured here is Belsotoma micantulum, a tiny little giant water bug that maxes out at a little over a half an inch long.  Pretty cute though, especially when munching on a mealworm that is WAY too big for her!  :)

flood

The only flash flood I've ever personally witnessed, though it's hard to see how big this flood was in this photo! Clicking on the photo will take you to a cruddy, low-res video I shot of it and posted on YouTube.

5.  At least one species has a nifty flood-avoidance behavior.  

Imagine you’re an aquatic insect and a flash flood is headed your way.  You’re going to be ground into a bloody pulp if you stick around.  What do you do?  If you’re the giant water bug Abedus herberti, you climb out of the stream before it floods!  This species crawls out of the water and walks perpendicularly to the bank until it reaches shelter away from the stream.  After the flood passes through, it crawls back into the water and carries on with its regular activities.  Awesome behavior!  And you can see a video of it online by visiting Dr. Dave Lytle’s website.  He filmed Abedus herberti leaving the stream after artificially simulating flood conditions with a fire hose.  The video is hilarious, so I encourage you to take 30 seconds out of your day to watch it.

Aren’t giant water bugs cool?  I love my bugs.  Considering they mostly just sit in one place hoping that food will swim by, it never ceases to amaze me just how many wild characteristics these bugs really have.  Hope you enjoyed this little peek into some of the many fascinating things these bugs have going for them!

_______________

Unless otherwise stated, all text, images, and video are copyright © TheDragonflyWoman.com

Advertisements

Friday 5: Webspinners

Welcome to another Friday 5!  I hope to get another dragonfly swarm data post out tomorrow or Saturday, but for now enjoy a short post about an insect that most people know nothing about: webspinners!

Behold, the mighty webspinner!:

webspinner

Webspinner, Oligotoma nigra

Okay, okay.  These insects aren’t that mighty.  In fact, they’re pretty soft, flexible little beasts and have a delicate structure.  Their wings are very easily damaged (more about why in a moment).  Basically, these are the 95 pound weaklings of the insect world!  But, these insect are still super interesting on many different levels and they deserve your love and respect in spite of their overall wimp factor.  Here’s why:

5. Webspinners belong to their own insect order, the Embiidina (sometimes called Embioptera).  As far as insect orders go, it’s pretty small, less than 400 species worldwide.  If you consider that one single family of beetles, the weevils, has over 40,000 described species, it really puts that number into perspective!  Most people will go through their lives without ever knowing that they exist too.

4. Webspinners aren’t very common in the US, so lots of entomologists get excited when they collect them in Arizona.  However, the most commonly collected Arizona species, Oligotoma nigra, isn’t native to the US!  It is an introduced species normally found in India and accidentally brought to the US, perhaps as early as the mid-1800’s.

3.  Webspinners are among the few insects that exhibit parental care outside of the ants, bees, wasps, and termites.  Females build nests and raise their young in them.  I’ve already written about webspinner parental care, so for more information please see my post on parental care in insects.

2.  Webspinners are sexually dimorphic.  The males have wings while the females are wingless.  (A more complete discussion of dimorphisms can be found on my post on color polymorphisms in dragonflies.)  The wings of the males are really cool too!  They are completely soft and flexible and utterly lack the rigidity of most insect wings because the wing veins are very soft.  They can fold, bend, curve, and otherwise move their wings in ways that are impossible in most other insects.  They have these soft wings for a reason: to allow them to maneuver easily in the nests of potential mates.  Webspinner nests are filled with narrow tunnels, spaces that would be difficult to navigate with stiff wings.  Most insects would become trapped within the tunnels when their wings became tangled, but the soft wings of webspinners allow them to move easily about the tight spaces.  On the other hand, such wings are completely useless in flight because they are too soft.  Never fear!  Webspinners have also evolved a means of making their wings stiff when they need to fly.  There’s a special pouch called the radial sinus along the front edge of the wings that they can fill with hemolymph.  When filled, the pouch acts like a wing vein, stiffening the wing enough for the webspinner to fly.  When he finds a nest, the male can deflate the wing pouch and make his wings floppy again before he enters the nest.  Pretty cool, eh?

1.  But the best thing about the webspinners is their web spinning abilities!  The nests they make are created from silk that is excreted from a special structure in their forelegs.  One part of the foreleg is enlarged (see it depicted here) and packed full of silk glands.  They then move their feet around, extruding silk, to create silken tubes in which to raise their young.  Now I could explain how they do this, but Sir David Attenborough is so much better at explaining these things than anyone else.  Enjoy this clip from his superb Life in the Undergrowth:

Webspinners!  They look like wimps but they have a sort of elegant charisma that few other insects possess.  And, they’re darner cute to boot!  They’re always going to be one of my favorite insects.

Next week’s Friday 5 will be a surprise!  Until next time!

_______________

Unless otherwise stated, all text, images, and video are copyright © 2010 DragonflyWoman.wordpress.com

Biological Trade-offs, or Why Brooding is Bad For Dad!

In biology, we talk a lot about trade-offs.  This usually means that when something gets better in one aspect of an organism’s biology, something else suffers.  Consider a tree species in a forest and its ability to survive a forest fire.  Now imagine that this species almost always experiences one type of forest fire.  If it almost always encounters the same type of fire, it probably doesn’t need to hold onto any of the traits that allow it to survive other types of fires.  Those traits require resources that could go toward other things – getting taller, growing faster, making more seeds or leaves, things that will help it survive the fire it always encounters.  Over time, the tree adapts to this fire and loses its resistance to other types of fires.  But what happens when a new kind of fire comes along, one the tree hasn’t ever experienced?  How well will it be able to resist that?  Because the tree has adapted so that it survives the fire it has always experienced, it has lost part or all of  its ability to resist new or very rare fires.  In this scenario, there is a trade-off between wasting resources to survive an event that almost never happens and using those resources to better survive the one that happens all the time.

Almost every biological organism exhibits trade-offs at some level, from viruses and bacteria to humans and other mammals.  Giant water bugs are no exception.  There are at least two major trade-offs related to giant water bug brooding: egg size and brooding costs (check out my post on giant water bug parents for more information about brooding behaviors!).  Let’s talk about egg size first.

Lethocerus indicus eating a small fish

Lethocerus indicus eating a small fish

Giant water bug eggs are, well, giant!  For aquatic insects, they have particularly enormous eggs.  In fact, one researcher, Dr. Bob Smith of the University of Arizona, has suggested that the size of the eggs was what led to the origin of brooding behaviors in the first place (Smith 1997 – full citation available at the end of this post).  Smith suggests that the giant water bugs started off a lot smaller than they are now and probably laid their eggs in water like most of their close insect relatives.  Giant water bugs are predators, and to become more efficient predators, they needed to get bigger.  In order to produce a bigger adult bug, Smith suggests they either needed to add an additional instar or they needed to start from bigger eggs.  True bugs, including the giant water bugs, almost all have 5 instars, so it seems that it is hard to for them to add one.  So, that left making the eggs bigger.  The eggs increased in size, allowing the bugs to become bigger as adults.  Eventually, the eggs got so big that they were no longer able to survive underwater, probably because they couldn’t get enough oxygen.  So, brooding evolved because the eggs got too big to survive without help.

In this scenario, there is a trade-off between making bigger eggs that require care, but result in bigger adults, and making smaller eggs that result in smaller adults, but do not require care.  You know which side of this trade-off eventually won: brooding evolved to allow the eggs to get bigger, and the giant water bugs became the huge, fierce predators that they are today!

Another trade-off relates specifically to the brooding behaviors of giant water bugs .  Brooding is likely bad for the father water bug, but the eggs do not survive if they are not cared for.  A water bug father thus faces this trade-off: he can care for his eggs, but at a cost to himself, or he can abandon his eggs to protect himself, but at the cost of his offspring.  Either the eggs are going suffer or the father is going to suffer.  Usually, the father makes a sacrifice himself in favor of the survival of his offspring, though the occasional aborted egg clutch has been observed.

So just why IS brooding bad for dad?  This is a question that several giant water bug researchers have addressed and there have been many suggestions.  Three broad categories of brooding costs have been identified (spelled out in an excellent paper by Kraus et al 1989):

Abedus herberti

Brooding Abedus herberti male

1. Brooding decreases a male’s mating opportunities. A male who is brooding cares for only one clutch of eggs at a time.  This means that while he is caring for eggs, he does not mate with other females.  If he did not have to care for his eggs, he could mate with many more females.  Thus, brooding decreases a male’s opportunities to mate.

2.  Brooding interferes with a male’s ability to move around. A brooding male experiences decreased mobility compared to non-brooding males.  At the very least, he is stuck in one place while he broods.  A back brooder has eggs glued to his wings, so he is unable to fly.  An emergent brooder has eggs stuck to a immobile object, so he can’t take his eggs with him if he needs to move to another location.  Back brooders might also suffers further costs including increased buoyancy (though Kraus et al provide evidence to the contrary), slower swimming speeds, reduced ability to find and capture food, and reduced ability to escape predation.

Lethocerus medius

Lethocerus medius brooding eggs

3.  Brooding increases a bug’s exposure to predators. Giant water bugs are big and full of high quality protein.  Brooding males are likely at a higher risk of predation than non-brooding males.  Back brooders may spend more time at the surface and have an increased surface area while they are brooding.  Emergent brooders spend more time out of the water while brooding.  In fact, a brooding emergent brooder is right out in the open, visible to everything!  Most emergent brooders will also try to defend their clutch from anything that might try to take it away, including predators and the occasional graduate students who need their eggs for their research.

So, brooding males sacrifice mating opportunities, mobility, and safety from predators to brood.  One might then ask, why do they do it?  One simple reason: giant water bug eggs do not survive if are not cared for!  Biologists generally believe that the ultimate goal of all biological organisms is to pass their genes on to the next generation.  If so, a male water bug will do whatever it takes to ensure that his offspring survive, that his genes are passed on.  This tips the trade-off in favor of the eggs, to the detriment of the father.

Next time, I’ll share another field story, one about an amazing water bug father who fought to protect his eggs as I tried to collect them.  It would make a good premise for a B-grade horror movie, and just in time for Halloween, so tune in!

Literature Cited:

Kraus, W.F., Gonzales, M.J., and Vehrencamp, S.L., 1989.  Egg development and an evaluation of some of the costs and benefits for paternal care in the belostomatid, Abedus indentatus (Heteroptera: Belostomatidae).  Journal of the Kansas Entomological Society 62, 548-562.

Smith, R.L., 1997.  Evolution of paternal care in the giant water bugs (Heteroptera: Belostomatidae).  In: Choe, J.C. and Crespi, B.J. (eds), The Evolution of Social Behavior in Insects and Arachnids, Cambridge Univ. Press, Cambridge, pp 116-149.

_______________

Text and images copyright © 2009 DragonflyWoman.wordpress.com

Kraus, W.F., Gonzales, M.J., and Vehrencamp, S.L., 1989.  Egg development and an evaluation of some of the costs and benefits for paternal care in the belostomatid, Abedus indentatus (Heteroptera: Belostomatidae).  Journal of the Kansas Entomological Society 62, 548-562.

Giant Water Bug Parents

Now that I’ve made a quick detour to talk about ants and other stinging insects and the dragonflies at a local wetland for a few posts, it’s back to the giant water bugs!  Today I want to go over parental care in giant water bugs.  If you remember from my post on insect child care, giant water bugs use a special type of parental care: paternal parental care.  This means that only the father participates in the care of offspring, and it is a very unusual behavior among insects.  So let’s go over how the water bugs care for their eggs!  First, though, I need to provide a little background information about giant water bug taxonomy (the organization of biological organisms) so everyone can make sense of it all.

I’ve already gone over the order, family, and American genera of the giant water bugs in previous posts, so I’m not going to go over them again here.  (Please see my taxonomy page for more information if you get confused along the way.)  However, there is another taxonomic group that falls between the family and the genera that I haven’t discussed yet, one that is important when considering paternal care behaviors in the giant water bugs.  This group is the subfamily.  You can easily tell when you are looking at a subfamily, at least when dealing with animals, by the suffix -nae at the end of the name.  Most giant water bugs belong to two big subfamilies, Lethocerinae (which includes only the genus Lethocerus, the truly giant water bugs) and Belostomatinae (which includes everything except Lethocerus, usually the smaller, rounder, and/or less robust water bugs).  There is one genus, however, that is very rare and only found in a very small part of South America, HorvathiniaHorvathinia is so rare, in fact, that researchers don’t even know where to look for it in the wild or whether it does any sort of paternal care like its close water bug relatives.  Horvathinia is generally placed within its own subfamily, Horvathininae, but some researchers think it might belong to either Lethocerinae or Belostomatinae instead.  Time and more DNA analyses will answer this question, but for now we’re going to ignore it.  After all, we don’t know what sort of parental care it uses, so we don’t need to talk about Horvathinia more here.

So, why do we need to know the subfamilies?  There are two basic known types of paternal care in giant water bugs.  These behaviors are known collectively as brooding behaviors – the word brood refers to a group of offspring all cared for at one time – and they are divided along the subfamilial lines.  This means that Lethocerus, a lethocerine, uses a different brooding behavior than the belostomatines, such as Abedus and Belostoma.  Let’s go over belostomatine brooding first as it is generally more familiar outside of the entomological community.  This is Abedus herberti:

Abedus herberti

Abedus herberti

Isn’t he a handsome father-to-be?  This is one of my favorite aquatic insects – I think they are gorgeous, amazing insects!  Take a look at those brown, round things on this bug’s back.  Those are the eggs that this bug fathered!  The belostomatines are back brooders, which means that the males care for the eggs attached to their backs.  How to the eggs get there?  In the belostomatines, the male and female mate, and then the female lays a few eggs on the back of the male.  The male then insists that they mate again (more about this in the next post), and then the female lays a few more eggs.  Several hours later, the female finishes laying whatever eggs she has available (up to about 150 in A. herberti) and leaves the area.

The male cares for the clutch of eggs on his back in several different ways.  All of the belostomatines carry their clutches to the surface periodically.  This allows the embryos developing inside eggs to breathe more efficiently – it is a lot easier to get oxygen from the air than from the water.  (In fact, providing oxygen in this way may be the primary function of back brooding behaviors.)  In the the bug you see here, Abedus herberti, the father further cares for his clutch by doing push ups underwater.  The eggs are able to absorb some oxygen directly from the water, so the push ups are probably a way to stir the water around the eggs and help the developing embryos breathe more efficiently when they are submerged.  Other species of belostomatines will do other underwater behaviors.  Eggs that are abandoned (male belostomatines can abort their eggs if they aren’t developing properly) or deposited anywhere other than on the backs of the male never hatch.  In contrast, almost 100% of brooded eggs hatch.  Brooding is thus an obligate behavior, one that is necessary for the continued survival of these species.

Now let’s take a look at how a lethocerine broods and compare their behaviors to those of the belostomatines.  This is Lethocerus medius:

Lethocerus medius

Lethocerus medius

As you can clearly see, the eggs are not on the back of the male in this species.  Instead, the eggs are laid on a stick above the water line.  Can you see them?  If not, take a look at the stick below the bug – those light colored, rounded blobs are the eggs.  (You can see a previously hatched clutch under the back end of the bug as well.)  This bug obviously cares for his eggs very differently than the belostomatine we looked at above.  If he’s not carrying his eggs around on his back, how does he care for them?

Lethocerus medius is an emergent brooder.  This means that the eggs are laid on vegetation above the water line instead of on the backs of the males.  However, like in the belostomatines, the eggs still need care and will die without it.  Giant water bug eggs have likely been brooded for millions of years.  During that time, it seems they have lost most of their ability to retain water.  Lethocerine eggs that are left out of water without parental care dry out so badly that the embryo inside dies.  So, lethocerines, like the one you see here, care for their eggs by bringing them water.  The male will typically remain attached to the stick that holds his brood, but is usually found at the base of the stick underwater, using his respiratory siphon to breathe.  Every now and again, the male will climb up the stick to his clutch and let all the water on his body drip down onto the eggs.  There is evidence that suggests that the males of some species might also swallow water that they then regurgitate onto the eggs.  Once the eggs are nice and wet, the male then climbs back down his stick and waits underwater until he has to water his eggs again.

So there you have it.  One group of giant water bugs cares for their underwater eggs by bringing them to the surface to get air and the other cares for their eggs, which get plenty of air, by bringing them water.  Pretty cool, eh?  Next time, I’ll discuss some of the costs and trade offs associated with parental care in giant water bugs.  In other words, I’ll be talking about why brooding is bad for dad.  Stay tuned!

_______________

Text and images copyright © 2009 DragonflyWoman.wordpress.com

Insect Child Care

As humans, we take the care of children for granted.  If you have a kid, you take care of it until it is old enough to move out and live on its own.  Lots of other mammals care for their children in similar ways, teaching their offspring how to survive in the world without their parents.  But this sort of parental care behavior is very rare in insects.  The insects I study, the giant water bugs, have a very special form of parental care and I’ll talk about that in my next post.  Today, I want to go over some of the different insects that use parental care so that you might learn a bit about the different ways that insects can care for their young.

This is a carrion beetle (also known as a burying beetle):

carrion beetle

Carrion beetle

If you follow my blog, I’ve talked about this beetle before in my post about my mold problem in my insect collection, so it should be familiar.  Carrion beetles are some of the more disgusting animals in the world, at least as far as most people are concerned, so please skip on to the next photo if you have a weak stomach.

So how exactly do carrion beetles care for their young?  Let’s go through the process, keeping in mind that it works a little differently from species to species.   First, the male-female pair finds a dead animal.  This could be a mouse, a snake, a bird, a small opossum – anything that’s in the size range a pair of beetles can handle.  Let’s say the beetle above has found a mouse.  The beetle and its mate will pull all of the fur off, roll the mouse into a ball (often colorfully called “mouse balls” in entomological circles), and bury it to prepare the carrion.  The pair will mate and then the female will lay her eggs near or on the carrion.  When the eggs hatch, the larvae will feed on the rotting carcass and the parents often help them feed.  The parents also help make the carrion last longer by eating fly larvae (maggots) that compete with their young for food.  Some carrion beetles spit digestive enzymes on the carrion to keep it fresher longer and others will carry mites that provide this service for them.  In fact, the parents are so busy taking care of the carrion that it requires both of them to keep molds, maggots, and other organisms from completely taking it over and depriving their children of food.  If the parents are successful, the larvae will feed for several days to a few weeks and go through all of their larval instars, then drop off the carcass to pupate.  At this time, the parents abandon the nest and leave their offspring to fend for themselves.  So, carrion beetles care for their young from the egg stage until pupation.  They are also among the very few insect species that have this sort of bi-parental (two parent) care. It is very unusual for both the father and the mother to care for the young.

A more common parental care behavior is the sort you find in the webspinners.  This lovely creature is a webspinner:

Webspinner

Webspinner

Isn’t he gorgeous?  These are actually rather unusual insects that aren’t common most non-tropical (i.e. temperate) locations.  Many entomologists will actually never see one of these alive in their lives!  Luckily for me, Arizona just happens to be one of the places where they are very common, so I was able to get some photos of this webspinner on my back porch one afternoon.

Take a look at the forelegs and look at the tarsi, those little segments near the end of the leg.  See that one big oval shaped tarsus where the arrow is pointing?  This is a specialized tarsal segment.  Were you curious why these are called webspinners?  If so, here’s the reason: that specialized tarsal segment contains a silk gland.  Webspinners are actually able to make webs!  They don’t make webs like most spiders though.  They make long, tube-like webs, called galleries, underground or in a food source.  The galleries are where the parental care takes place.  A male and female webspinner mate in a female’s gallery.  The male leaves right away and the female lays her eggs in her gallery.  As the nymphs hatch, they live within the gallery of their mother under her care.  When they reach the adult stage, they may leave the nest to find another place to live (especially if they are males – they don’t stick around in their mother’s nest very long) or continue to live in the gallery, expanding it so that it fits more and more individuals.  This sort of parental care should sound very familiar, even if you know very little about insects.  If it’s not coming to you right away, I’ll give you a hint: ever see an ant farm?  Webspinner galleries are a lot like ant nests and the sort of care that they exhibit is very ant-like.  One female establishes a nest that can end up containing several generations of offspring.  Paternal care by a single adult female is relatively common among insects, especially in the social insects like ants, bees, and wasps.  But webspinners are rather different from the ants, bees, and wasps too – they don’t have one single female who produces all of the offspring in the nest.  The female who establishes the gallery originally produces a second generation and might produce several more, but the other females in the nest are all able to produce their own offspring as well.  So, to recap, webspinners use maternal parental care (the female parent cares for the young) and care for their offspring from the egg stage through adulthood, and even sometimes beyond!  This is very different than what we saw in the carrion beetles where both parents were necessary for the survival of the offspring and care ended as soon as the larvae pupated.

Now we’ve come to the really rare parental care behavior: paternal care, or care only by the father.  This sort of behavior is only known in a VERY few insects, including the golden egg bug (Phyllomorpha laciniata) and the giant water bugs.  I’m going to talk about the giant water bugs in more detail in my next post, so for now, check out the photo of the golden egg bug at this link:

http://www.koleopterologie.de/heteroptera/5pent2/coreidae-phyllomorpha-laciniata-foto-guenther.html

(I apologize for not having my own photo, but these are only found in Europe and I’ve never been there.  I’m also not keen on stealing other peoples’ photos without permission.)  Did you see the gold colored eggs on the back of the male in the photo?  These bugs are, like SO many other insects, named after a characteristic they possess.  These bugs have bright gold eggs, so they’re called golden egg bugs.  So how do they care for their offspring?  This species is probably just evolving their paternal care, so it’s still a bit sloppy compared to the elegant system you find in the giant water bugs, but here’s the general idea of how the system is thought to work.  The eggs of these bugs have traditionally been laid on plants near the ground.  However, the vast majority of the eggs left by themselves are eaten by ants.  The females of this species are therefore starting to deposit their eggs on the back of other members of their own species, mostly the males, gluing them to the backs of these individuals so that they are protected from the ants until they hatch.  The bugs themselves don’t like having ants on them, so they’re inclined to keep the ants away from the eggs they carry as well.  Pretty neat huh?  The offspring thus benefit from the selfishness of the adult that carries them.  I call this a sloppy system because females basically have to ambush a mating pair to be able to lay eggs on their backs.  Most golden egg bugs really don’t want to carry the eggs and will try to get away.  Mating pairs have more important things going on and keep doing what they’re doing while another female lays her eggs on the male.  The male bugs then carry the eggs around with them until they hatch, at which point the egg shells fall off.  Golden egg bugs thus care for young only in the egg stage and then the nymphs are on their own.  Unlike the carrion beetles, only one sex usually cares for the eggs, and unlike the webspinners, the males are usually the caregivers.  In the giant water bugs, the other insects that use paternal parental care, the system is a little different.  The male and female mate, and then the female lays her eggs in a way that ensures that the male cares for his own offspring.  The females mate, lay their eggs, and leave.  The male is left on his own to care for the eggs until the nymphs hatch from them.

Paternal parental care is probably the most rare form of parental care known in insects, but all of the giant water bugs observed to date use this form of parental care.  Tune in next time for more information about the amazing parental care system of the giant water bugs and prepare to be dazzled and amazed!

_______________

Text and images copyright © 2009 DragonflyWoman.wordpress.com