Showing posts with label Insects. Show all posts
Showing posts with label Insects. Show all posts

Sunday, 23 November 2008

The Queen Bee - Not As Royal as you may Think!

The Queen Bee is a remarkable insect. Here, follow the life cycle of the queen, from the egg to the end. You may be surprised at some of the things you find out!


This is an example of a Queen cell. The conditions in the hive have become right for a swarm and when this happens the old queen lays eggs in to queen cups. These are larger than the normal cells in to which eggs are laid and have a vertical orientation, while the normal eggs are vertical. Swarm cells will hang at the bottom of a frame within the hive. When an “emergency queen” is needed (otherwise known as a supersedure), then the cells are built out from the face of a frame. These queen cells may look like a super-sized peanut but they hold something in side much more precious than a nut!



Workers will “decide” that they want to swarm for a number of reasons. As the population of a hive increases it gets rather cramped and a new hive is often needed. For the hive to function a new queen will be needed to populate it. In order to maximize the survival of a new hive, often a number of queen cells will be constructed. When the newly hatched queens emerge they will fight to the death. The winner will then destroy any unhatched queen cells and the swarm will begin. The workers above are beginning the construction of a new queen cell.




A cutaway of a queen cell shows the alien being developing within! It is not difficult to see where some Hollywood movie makers get their inspiration from! There is not a huge amount of time between the laying of the queen egg and that queen itself starting her own enormous family. The egg will hatch three days after it is laid and the larva grows and molts after that. On the eighth day the queen cell will be capped and the pupa stage will begin. The virgin queen will emerge on around the sixteenth day and take flight three to four days later. She will start to lay eggs herself from around the twenty third day. Amazing!



One of the reasons that the queen cell is so much bigger than a normal egg cell is that the queen has an enormous abdomen. This is a biological necessity – she is destined to become an egg laying machine. Spot the blob of blue paint on her thorax – something that beekeepers do to quickly locate the queen among her minions. If one of her daughters leaves the tank in a swarm, then they can take tens of thousands of bees with them. This will involve about five kilos of honey taken along for the ride. The beekeeper will usually remove queen cells – as they obviously don’t want to lose all that honey – often to an empty hive of their own.



The virgin queen that survives will fly to what is known as a “drone congregation area”. She will mate with around a dozen drones and store the sperm in her spematheca. This is an organ designed to receive and store sperm until it is needed. It is more often than not the place where fertilization occurs as well.



She has a small window of opportunity here, though! If she does not mate within a few days then she will become a “drone layer”. As she will have no fertilized eggs that will spell the end of the colony. In very rare cases, something called thelytoky has been known to happen. This is where worker bees will lay the eggs of a new queen themselves, thus saving the colony. This is restricted to a few species, such as the Cape bee.




Do bees make a noise other than buzzing? Yes – and it is known as piping. This is produced by virgin and mated queens at certain times. The virgin pipes as she comes out of her cell. Once she has mated she may do it for some time afterwards as well. If you imagine a child’s trumpet, then you have a fair approximation of piping and it is audible to the human ear outside a hive! People argue as to its reason but most see it as a kind of battle cry. It is created by the flight motor (the wings, however, do not move when piping occurs). Others believe that it is a rallying call to workers and the best piper will get the most drones to follow them.




Many people believe that when bees swarm they are at their most dangerous. In fact, the opposite is true in reality. A swarm of bees is actually a fairly docile affair because, after all, they have no hive to protect at the moment, so what would the point be in stinging people. That said, it is best to be careful – especially if you are wearing primary colors – and stay clear. Nature is best left alone in these circumstances!



This can also be done artificially. As you can see, however, it is a process that involves great care and a deal of equipment. However, just as in the artificial insemination of mammals, this will ensure that the next generation the queen reproduces it exactly the one that the beekeeper desires. This will help eradicate pests such as mites (see below) and ensure some good honey in the process!



A common mistake amongst non apiarists is the assumed fact that the queen directly controls the hive. Effectively, however, her duty is as an egg making machine. She can lay bout two thousand eggs a day in the spring. This amounts to more than her own weight in eggs each day. Surrounded continuously by workers, she needs for nothing. They give her food and take her waste away. They will also collect a pheromone which they then distribute to stop workers from starting queen cells.



This very close up of a queen bee shows one of its greatest – and smallest – enemies. The bee mite is an external parasite that attacks honey bees. It attaches itself to the bee’s body and sucks out its hemolymph. This is the blood analogue that is used by bees as they have an open circulatory system. Unfortunately the mite is more than just a pain in the neck. It can spread a host of viruses, including “Deformed Wing Virus” (does what it says on the packet) and the arrival of mites in a colony can often spell its demise. Scientists believe that the mite may contribute to the Colony Collapse Disorder (otherwise known as CCD) that is spreading throughout the United States.



Often a new queen will emerge from the hive already badly infected with mites. Here, if you look just behind the eyes, you will see some light orange bumps. These are the mites that have already sentenced this particular queen to an early death. The mites have been kept at bay by antibiotics for twenty years or so. Unfortunately, this can make problems worse by producing a strain of mite that is resistant to the antibiotics.

Wednesday, 5 November 2008

The Weird Life Cycle of the Ladybug

The Ladybug has something of a strange life cycle and one that surprises many people. From egg to fully grown ladybug, join us on a journey of a lifetime - literally!



The ladybug will always try and mate as close to a colony of aphids as possible. When its larvae hatch they will then have a ready made food source upon which to feast. When the eggs are laid they are only about a millimeter in length and the numbers can range from a few right up to several hundred, depending on the conditions.



The male has an insect penis which is called an aedeagus. A “lock and key” fit means that if he gets it wrong and tries to mate with another species of ladybug, he will not get to third base! Fertilization, as you can see, is internal, which surprises many people. It doesn’t exactly start with a kiss, but with a little Barry White in the background this could almost be classed as romantic! Almost, but not quite!



Harmonia axyridis lays its eggs. Many people believe that the ladybug will lay the same amount of eggs each time it mates. This would be true if conditions were always at a constant: what happens is that when conditions are harsh, the ladybug will lay many eggs that are infertile. Only laying a few eggs that will hatch is not just to maximize the chances of survival of those that are fertile, however. The infertile eggs will actually provide sustenance for the lucky ones who survive through to hatching before they start roaming for live prey. If times are harsh, however, this particular species will gladly feast on the eggs of other ladybugs and different species of insects.



This particular set of eggs belongs to the species Harmonia axyridis which is also known as the Harlequin Ladybug or Asian Lady Beetle. It was first introduced to North America and Europe by man in the early twentieth century as a way of controlling scale insects and aphids, which it devours readily and in huge numbers. In some parts of America it is also known as the Halloween Lady Beetle because it is found in many homes in the month of October. This is because it likes the warmth of human habitation and so is drawn their for its winter hibernation period (yes, Ladybugs hibernate!).



Hatching takes place after three to five days, which is pretty quick, even for an insect the size of a ladybug! Six legged larvae about one eighth of an inch emerge and start devouring as many aphids as they can – they have quite a metamorphosis to undergo before they are adult and they need as much food as they can get! If the conditions are right, then the larvae will grow very quickly. The whole process from egg to adult can take as little as twenty four days.


The ladybug larva goes through several stages and is best described as looking something like an insect equivalent of a crocodile, only black and with (occasionally) orange markers. The larvae eat about twenty five aphids (or equivalent!) a day. That’s nothing to what the adult can get through – roughly about fifty. This is why many ladybugs are popular with farmers and gardeners. In fact their name comes from a time in the Middle Ages when people thought that they were sent as a gift from the Virgin Mary to help with controlling pests. It is not, as many people believe, a protogynous hermaphrodite. This is when an animal begins its life as a female. So, if you thought they were so named because the vast majority (or as some believe, all of them!) were female, then put that thought out of your mind!



Many people assume that the ladybug – adult and larva alike – have only one food source, that is the aphid. Again, this is not true. They will eat scale insects (such as the cochineal). They will also make a tasty meal out of any mealybugs they come across (mealybugs are unarmored so make an easy and tasty meal!). They will also eat mites, which to our eyes are pretty much invisible, but to a ladybug will make the equivalent of an in-between meal snack! Does the (some would say poor and unfortunate) aphid have any protection? The only defense it has is gravity! Aphids will simply let themselves fall off the leaf if they can, and plummet to the ground, in order to escape being on the day’s menu.



There isn’t much respect between the species, either! Here, a Harlequin ladybug makes a meal out of one of the smaller native ladybugs in a US garden. The Harlequin is becoming such a nuisance in some places – and a threat to local biodiversity because of its size and voracity – that ways of getting rid of the species from Europe and the US are being looked in to. This may involve the introduction of its natural parasites from Asia. Let us hope that the home grown species are immune!



When the larva has grown to its full size it will then attach itself to the stem of a plant. It splits along its backside and exposes the pupa underneath. This sounds like something out of one of the “Alien” films and it really doesn’t take long to figure out that they didn’t get those ideas straight out of their imagination! The pupa, though, is wrapped up in this final stage of its metamorphosis and so is safe from the elements – but not from predators. It is at this stage it is at its most vulnerable. If it approached close to its hatching time by a possible predator it will shake itself dementedly to try and warn off the unwelcome visitor! This last stage takes just a few days and then the adult ladybug is ready to emerge.



Like any newly hatched insect, the ladybug must take some time to ‘dry out’. When it emerges it is completely soft and its exoskeleton and elytra (see below) must harden. This is made of chitin, which is a protein much like the one that creates our fingernails. For the first twenty four hours or so the ladybug will have no spots. Then it will go and find its first meal. Recently, four ladybugs and a whole heap of aphids were sent up in to space to try and ascertain how the aphid would try and escape from its enemy without the assistance of gravity. With some time to while away, the astronauts (on a 1999 mission) gave the four bugs names: John, Paul, George and Ringo. The result of the experiment? Ladybugs do very well in space, aphids don’t! Quel surprise!



Adult ladybugs come in a variety of colors and these are no accident. In nature there are colors that warn off potential predators. The main colors that the five thousand (or so) species of ladybugs have are red, black and yellow. Unsurprisingly, these are exactly the colors that tell would be diners that this dinner is not going to taste very pleasant! Ladybugs also have one other trick up their sleeve. They ‘play dead’. They pull their six legs up so they cannot be seen and do a ‘reflex bleed’. This is when they excrete a little amount of their ‘blood’ (which is yellow and smells horrible to predators). Anyone reading this that could once have been classified under the genus “boy” and who had a fascination with insects will recognize this little trick of the ladybug!




The ladybug uses the part of its body which gives it its color for more than just protection from predators. The elytra (if you can’t remember that, then you can call them shards) on its back are actually a modified forewing. Instead of using it to fly, the ladybug uses it to protect its hind wings, which are positioned underneath. Although it can get battered over time, it usually ensures that the ladybug retains the power of flight for the duration of its life (which is usually anything up to nine months). In some species of bugs the elytra fuse with the hind wings – and so we have the thousands of varieties of insects that cannot fly!




This of course, is not the case with the ladybug. It is one of the most popular insects on the planet (certainly among children) and has found itself at the center of many a myth and legend – as well as the occasional nursery rhyme. As the next generation flies off to feed and mate, perhaps it is appropriate to end with the most famous (in the English language at least). We will leave it intact, with its original UK English name – “ladybird”.



“Ladybird, ladybird, fly away home

Your house is on fire and your children are gone

All except one, and that's Little Anne

For she has crept under the warming pan.”


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