Ladybeetle by Max Johnson
When I look at my blog entries and realize that my last piece was in early December 2009, I defend myself by insisting that I was not asleep at the keyboard – I was in a special state of renewal and recuperation – maybe a diapause – like the Japanese Ladybeetles that invade my house each fall, or a period of “estivation.” I like the sound of “estivation” over the other choices: hibernation, brumation, viral dormancy, and seed dormancy.
Estivation
“Estivation” sounds moderately intellectual, doesn’t it? As if I was goofing off but thinking hard about it. However, I learn that this state is one found mostly in invertebrates like snails and worms responding to very hot or very dry conditions. Hmnn. That does not sound like the winter we just had.
Predictive and Conditional Dormancy
Some forms of dormancy occur before the adverse conditions set in. An environmental cue (like decreasing hours of daylight) predicts the onset of hard times such as winter or drought, and the organism enters a protective dormant state before the harsh conditions occur. Other critters will wait for survival-threatening circumstances to develop and then enter a dormant state. Seeds and certain microscopic entities like pollen grains and bacteria can exhibit this conditional dormancy to a remarkable degree. Apparently, people have germinated seeds that have been dormant for over 1000 years! I won’t mention the special latency skill of herpes-type viruses (including chickenpox), that wait in hiding inside our cells, latent until something very bad or very good (illness, chocolate) awakens them. Shhh.
Hibernation
Most of us are familiar with the predictive hibernation strategy used by many mammals. They build up body fat in the summer and fall (sound familiar –all that pasta, all those glasses of wine?), and before it gets really cold they head for a hidey-hole, decreasing their heart rate dramatically (by as much as 95%) as they enter a sleeping state and dream away the winter.
Brumation
In brumation, a similar predictive strategy employed by reptiles, the creature (such as a lizard) does not actually sleep, but is less active and requires little to no food, However, it does still require water and will become more alert and will move in order to drink, and then resume brumation. This sounds a bit like my teenage son when it is time to get up for school. He does not arise, but will become more alert and move slightly (even talk briefly) in response to maternal distress calls, but then resumes brumation.
Inhalant Insect Allergy
Years ago when I first researched the life cycle of the Japanese or Asian Ladybeetle, I learned that it typically undergoes diapause under tree bark. I figured my house probably seemed like a big tree and that’s why I had an infestation and consequent sneezing and itchy, watery eyes. Diapause occurs in many insects, and in a few mammals. Insects temporarily suspend development during the fall and winter cold months, and then resume activity in the spring.
In the case of the Asian Ladybeetles, although they enter the walls during the fall, after a cold snap, and rest for a while, when we begin to heat our houses for the winter, they gravitate out of the walls to the warmth, thinking “it’s Spring!” and we have them flying into light bulbs, falling into our open cooking vessels and generally making a nuisance of themselves. In mammals like the Roe deer, the diapause strategy temporarily delays implantation of an embryo, to ensure that all offspring are born in the spring. Rest assured, this process in deer is being studied for all its potential applications.
In the late 90’s there were just a few descriptions on the internet of ladybeetles invading houses, and none of allergic responses to the non-native species. I did find a nifty description of an indoor ladybeetle trap – (bucket, UV light, slippery metal deflector and baby powder!) which I have used ever since. Now there are lots of clinical research abstracts on allergic rhinitis induced by “inhalant insects” (Curr Opin Allergy Clin Immunol. 2009 Aug;9(4):329-33).
So that’s my other excuse for the diapause of the blog: my immune system was in full scale revolt against airborne ladybug allergens and I was…sleepy. But it’s spring now and the blog is back!
