Cockroaches

Hated by many but liked by some

Finding a cockroach in an unopened bottle of Cola isn’t exactly “cool”. Seeing them scuttling along the kitchen floor at a top speed of 2 metres per second in the large Periplaneta americana and leaving their distinctive odour on some plates they might have run across at night isn’t very pleasant either and yet, there is some information about them which is not entirely negative.

First of all, despite their less than positive reputation, they are not know to carry or transmit diseases; they neither sting nor bite and amongst several cultures in various countries cockroaches and their egg cases are a part of the traditional armamentarium to combat certain diseases and dysfunctions. In the year 2000 E.M. Costa-Neto and M.V.M. Oliveira published an article in the journal Human Ecology Review, titled “Cockroach is good for asthma: zootherapeutic practices in NE-Brazil”; the world’s largest cockroach farm is breeding 6 billion cockroaches a year, using artificial intelligence to manage a colony larger than the world’s human population – all for medicinal uses or a source of protein for livestock feeds. There are many such cockroach breeding facilities in China, but no other matches the productivity of that in Xichang (S.W. Sichuan province). If after all this, I now report that some people enjoy eating cockroaches, fried in oil and seasoned with spices, I suppose nobody will be surprised any more.

I loved to use cockroaches in my comparative physiology course “Animal Senses and Behaviour”, because it was easy to demonstrate electrophysiological recordings with them and the fact that they “hear” with the two horn-like projections (known as “anal cerci”) at their rear end. To prepare them for the recordings is easy, as their ladder-like ventral nerve cord is accessible from the dorsal side of the animal after most of the inner organs have been removed. With two fine silver hook electrodes pushed under the connectives between two nerve ganglia, I could then carefully lift the nerve cord ever so slightly above the cockroach’s body liquid and record its nervous activity to be displayed on an oscilloscope. I then got my trombone and played short bursts of low or high frequency tones. The lowest frequencies picked up by the anal cerci elicited a train of responses in the nerve cord and showed the students that the information from the anal cerci was passing on the way to the brain of the cockroach through the ganglia responsible for leg movements. The same preparation was also useful to demonstrate the response to shadows when I passed my hand or my fingers across the insect’s eyes.  I need to add that cockroaches (and some mutations like white-eyed individuals) have been used in research on vision and visual information processing in a variety of scientific laboratories. Most roaches, are easy to breed, are undemanding, live for 6 months and some, like the Hissing Roach, even make pets.

That one can even have fun with cockroaches I learnt when I was a sailor, because ships almost always have cockroach stowaways, especially the small German species Blatta germanica. A bit of ground coffee put in a glass with butter or some other fat smeared on the upper rim of the glass’ inside would trap some of the nocturnal creatures and, competing with each other, we could find who had caught the most roaches the next morning. We also organized cockroach races to see who had the fastest insect.  Cockroach species occur in a variety of habitats (and not just in human dwellings). That there are even aquatic species that dive into a stream or pond, I only learnt recently in Northeast India, but that some species give birth to live young and feed their offspring with a kind of “milk” or that some can reproduce without males, I knew before. Having been around for about 300 million years, the cockroach “tribe” will almost certainly still be there when humans have become extinct. So: hats off and some respect to these little unwanted and unloved champion survivors. There is even a song dedicated to them: the Spanish folk song “La cucaracha” and when a cockroach would fly into our house in Jamaica (they DO fly when the temperature is well above 30⁰C), I did not kill it, but picked it up and returned it to the garden. Sounds crazy to many, I guess, but will be understandable to some (I hope).

© Dr V.B. Meyer-Rochow and http://www.bioforthebiobuff.wordpress.com, 2021.
Unauthorized use and/or duplication of this material without express and written permission from this site’s author and/or owner is strictly prohibited. Excerpts and links may be used, provided that full and clear credit is given to V.B Meyer-Rochow and http://www.bioforthebiobuff.wordpress.com with appropriate and specific direction to the original content. 

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Why are there honey bees on Heligoland

When there shouldn’t really be any?

The small 1.4 km2 large German North Sea rock island of “Heligoland” (in German “Helgoland” and in the local Frisian language “DeatLun”) is a fascinating place. By 1400 the island had been one of the hideouts of the pirate Klaus Störtebeker (meaning “emptying one mug of beer in one gulp”). In 1890 the island was given to Germany from England for the German colony of Zanzibar (which then became British), but before it became British in 1814, Helgoland had been claimed by Danish, Swedish and Dutch rulers. After World War II, when the island (after it had been made into a fortress by Hitler and ‘survived’ attempts by the British 1947 to bomb it into oblivion), it became a famous taxfree haven and tourist resort. I love this unique place and have followed its growth and recovery ever since I had first visited Heligoland in 1955.

When the sun shines and there is no wind (which is rare) this small island can be a magically beautiful place and when in the summer of 2019, I went there with my wife, we were in luck: fantastic weather the whole week. The sun was shining, blue skies, colourful flowers everywhere, bees humming from one inflorescence to the next….But, hey, honey bees? Real honey bees?  There shouldn’t be any, was my immediate thought. It was impossible they could have reached this oceanic island 60 km from the German mainland; bees do not fly across water  – even a small lake is an obstacle for them. I was puzzled. Besides the small area of the island and consequently limited pollen and nectar source would certainly have precluded any bee culture on the island. It annoyed my wife a bit that suddenly I seemed to be more interested in the island’s bees than her (at least until I had solved the puzzle).

The solution was this: successful beekeeping all over the world is associated with conserving the best possible genetic make-up of the queen with target characteristics such as the capacity of honey collection or disease resistance of her and her offspring. For the conservation and improvement of the genetic diversity of the bee, artificial insemination with selected drone bees or having a remote island mating location are the methods of choice. Heligoland is an ideal place to conduct controlled matings to produce honey bee queens with desired characteristics without genetic contamination or mix-up. That is why in one summer season between May and July approximately 80 virgin queens, each with about 600 worker bees, are taken to Heligoland from several locations in northern Germany by ship.

To ensure that high quality drones are present prior to the arrival of the virgin queens, drone hives are placed a fair distance away from the queen mating apiaries. A full frame of drone brood will produce around 700 mature drones, which may live up to 60 days but exhibit declines in fertility after 28 days. It’s been calculated that for 200 virgin queens one needs to have 8 drone mother colonies and for 80 virgin queens one would require perhaps 2,000 high quality drones. A single queen on her nuptial flight (or three or four flights) may mate with several drones and once successfully inseminated queens will be returned to its owner about 3 weeks after the excursion to the honey bee’s “Love Island”. Stray drones (other than the selected high quality ones) can simply not be present there and I learned that annually around 150 virgin queens are taken to Heligoland. One can imagine how happy the bachelor drones must be when the virgin queens arrive! Alas, all drones lose their genitals after mating once and die.

I also learned that not every virgin queen is equally attractive to drones and that queen bees that had already mated with several males were of particular interest to other males. That reminded me of what had been termed the “wedding ring effect” by researchers who had noticed the preference of young human females for men that were married, apparently because such men signified “quality”. But perhaps there was also some competitive element or maybe even ‘envy’ involved. Anyway, I didn’t share this snippet of information with my wife, lest she’d get worried about her husband.

© Dr V.B. Meyer-Rochow and http://www.bioforthebiobuff.wordpress.com, 2021.
Unauthorized use and/or duplication of this material without express and written permission from this site’s author and/or owner is strictly prohibited. Excerpts and links may be used, provided that full and clear credit is given to V.B Meyer-Rochow and http://www.bioforthebiobuff.wordpress.com with appropriate and specific direction to the original content. 

Blind as a Bat: Certainly Not

And also not bad or beastly   

In the early 1980s in Finland I met a bat researcher who explained to me a device called the bat detector which works by changing the high frequencies of a bat’s cry, inaudible to humans, into audible lower frequencies. That device allows the researcher to look for the bats that s/he then knows are around. Sadly, that very bat researcher died in 1985 after being bitten by a bat that had transmitted the rabies virus to him. This was such a rare and isolated case in Finland that it made headlines and led to a hiatus in Finnish bat research. Despite the fact that bats can indeed harbour loads of viruses and other pathogens (but don’t get sick themselves) and may be pestered by parasitic flies of the families Nycteribiidae and Streblidae (because of the bats’ habit to be colonial, which involves close contact between individuals), they are, generally, of absolutely no danger to humans. Their life is an alien life that can last 40 years, a life in the dark, a quiet and secret life (except that of the thousands of fruit bats in Australia roosting in trees of parks and gardens). However, bats are absolutely fascinating mammals and earlier I already pointed out some of their remarkable reproductive adaptations with suspended pregnancies and (in some species) milk-producing “father bats” helping “mother bats” in parenting.

There are at least 1200 species of bats, which means 20% of all mammals can fly. Their sizes range from that of a bumblebee to that of a small dog but none of them is blind; a fossil Burrowing Bat from New Zealand is estimated to have weighed 40 kg. Their food habits are amazingly varied: some tropical species are important pollinators and visit flowers, others munch leaves or attack fruits; many species feast on insect pests like moths and beetles that fly around at night and some (the fish-eating bats) have even become accomplished piscivores. The notorious vampire bat of Central and South America is the only mammal that depends on blood for its diet, but although that may not be very nice, their habit of sharing a blood meal through a kiss with a colony member that hadn’t been able to find a food source shows an altruistic side. It is well known that bats form friendships with other bats and that bat orphans will be adopted by not even genetically closely related individuals of a colony. Bats are not blind but locate obstacles and food in the dark by echolocation (which I mentioned in an earlier blog).

Scientifically referred to as Chiroptera (from Greek “cheir” = hand and “pteron” = wing), bat wings are the result of a thin membrane between four of their fingers and are thus analogous to bird wings. Being able to fly, bats colonized far away islands like New Zealand, Hawaii and Galapagos, but being nocturnal only a handful species could survive in northern Finland despite the abundance of mosquitoes and other insects in the summer (only daylight in summer nights). The cold and long winters are no problem: many species enter into a state of torpor and hibernate in caves or other sheltered places. To rest and roost, most bats hang upside down, which required special adaptations with regard to their hind extremities, joints, muscles, tendons and circulatory system (a human would die if in an upside-down position for too long). An exception, as Daniel Riskin & Paul Racey could show in 2010, are sucker-foot bats like the Madagascar Myzopoda aurita: it clings head-up to leaves using specialized pads on its wrists and ankles.

I’m not aware of bats other than the large fruit-eating species being consumed as food by humans, but falsely accused of being a symbol of evil in many western societies, people should focus on the charming side of bats and revere them as harbingers of Good Luck and Prosperity as in some parts of China where bats often adorn wedding cards. Actually, in Europe killing a bat can result in hefty fines – that’s a start.

© Dr V.B. Meyer-Rochow and http://www.bioforthebiobuff.wordpress.com, 2021.
Unauthorized use and/or duplication of this material without express and written permission from this site’s author and/or owner is strictly prohibited. Excerpts and links may be used, provided that full and clear credit is given to V.B Meyer-Rochow and http://www.bioforthebiobuff.wordpress.com with appropriate and specific direction to the original content.