A Cockroach in the Cola

Is not what you expect (or want)

During my first three years as Head of the Electron Microscopy  Centre and Professor of Experimental Zoology at the University of the West Indies in Jamaica I managed not to drink a single Cola  – not because I don’t like Cola, but because I like the brown and refreshing drink too much and knew how easily I could get ‘hooked’ on it. However, during my last and fourth summer I began to drink Colas, first one bottle a day, then two, three, even four…  until the evening when I was ready to open a bottle and spotted a huge dead cockroach in it! The next day I took the unopened bottle back to the shop where I had bought it and the shop owner apologized and assured me that he’d let the supplier know what I had found and that I should leave my name and address. A week later I received a gift from the Cola company: a wooden chest full of Colas (I won’t reveal which company): all without cockroaches in them.

Well, if that wasn’t bad enough, imagine what happened to my colleague Peter in New Zealand after he obtained a bucket of raw honey from a beekeeper friend of his: he found a dead but well-preserved mouse in the honey when he lifted the lid! Being a honey researcher, he knew of course that honey preserves and kills bacteria, but when he wanted to give me a jar of that honey I politely declined. I think he brightened up somebody else’s life with that honey, who saw Peter as a generous and caring person.

Stuff in food items that really shouldn’t be there is not as rare as many think. When I worked as a steward on a ship and a passenger wanted a plate of some buckwheat or oats (I can’t remember exactly what it was, but she insisted “raw, not boiled”), I noticed that our oats/buckwheat was crawling with tiny dark beetles. Well, since that passenger always brought her little dog to breakfast, I wasn’t too worried, thinking the oats/buckwheat would be for the dog. When I brought her the plate, I saw to my horror that she was pouring sugar and milk over the oats and commenced to eating it herself! Since she seemed satisfied, I did not ask her if she liked the breakfast, but rushed to tell my colleagues in the pantry. Incidentally, she did not get sick, but she also never asked for raw oats or buckwheat again on the trip. My first wife had a friend by the name of Heather with whom she often went shopping at the open market. This Heather took great care to examine lettuces and she wasn’t satisfied until she found one with a little slug or snail hiding in it. That, rightly or wrongly, indicated to her that the lettuce had not been sprayed with insecticides or undergone some other chemical treatment. But would this health food lover have loved to know what kind of “filth in food” is legally allowed in food stuffs sold in the USA?

The FDA (= Food and Drug Administration) stipulates that coffee beans for your coffee may contain an average of 10 mg of animal poop and 4-6% of mouldy beans. A teaspoon full of pepper can contain 40 insect fragments, while for every 8 ounces of raisins (227 g) 35 fruit fly eggs and approx. 10 whole insects are tolerated. In a 16 oz (454 g) box of spaghetti 450 insect parts and nine rodent hairs are acceptable. Two maggots in a 16 oz (454 g) can of tomatoes are not illegal and neither are 20 or more maggots of any size in a 4 oz can (113.5 g) of mushrooms. Sweetcorn, may also be contaminated and for every ¼ cup of cornmeal an average of one insect, two rodent hairs and 50 or more insect fragments or one or more fragments of rodent dung may be present. If frozen or canned spinach does not contain the permitted 50 aphids, then the FDA allows larvae of spinach worms or eight whole leaf miner bugs. Regular food controls are necessary and standards need to be set, but most of all the food must not make the consumer sick. Perhaps the aforementioned Heather is right and insect-containing food is safer than that which has undergone chemical cleansing. However, I’m not so sure about the permitted rodent hairs and dung. This reminds me of the fingernail I once found embedded in a Cadbury chocolate bar that I’d sent to the company and complained about, but then never got a reply. I changed the brand.

Bonus: THE SALON STEWARD from “Fake, Fact & Fiction”

The xylophone had sounded for dinner. The other two passengers and the two of us strode, a little off-balance but joyfully in anticipation of the usual gustatory delights, towards what on this ship was termed the ‘salon’, where our steward in his smart uniform already stood in attendance ready to bow at our entry and greet us with a witty welcome comment.

On a long monotonous sea-journey such as this one, the meals are always a gratifying respite and my husband and I were looking forward to them all day long. What a pleasure it was when our steward helped us into our comfortable dinner chairs and when we were gathered together around the dinner table in the company of the captain, the first officer, and the chief engineer.

For a full two months we had been enjoying the hospitality and attention of this fine young lad, who cleaned our cabins, who served us our meals, who never turned down a request for help, and who was genuinely friendly to us. We really liked him: “our” salon steward.

And here he came again, virile, panther-like, confident. Sure-footed despite the rolling sea, he balanced the hors d’oeuvres on a silver tray and placed them elegantly in front of us. A shock of black hair cheekily covered part of his high forehead and no matter how “jumpy” the boat and how rough the sea, never would he spill a drop of the soup or hesitate to carry three plates at once, in one hand, to our places.

Nothing seemed to go unnoticed by him and salt seller, sauce bottle, pepper shaker, jug of water, etc. were always on the table just like the starched and ironed serviettes. He was an unusual steward, who did not smoke or drink, which made him all the more amiable. Even his beard, which at first had seemed a bit out of place on a steward, now was a definite ‘plus’ and gave him character, even dignity. Were we in need of some expert nautical or geographic information and was the captain not around, who would come to the rescue and provide a humble, but correct answer to our question? Our steward!

We were hungry (even doing nothing aboard a ship on high seas makes you hungry – and this was not a cruise ship, but a freighter that accepted up to ten adventurous passengers). The chicken salad on toast looked delicious. Our East Asia part of the “Round-the-World” trip was nearing its end. “A relaxing experience for body and soul on a genuine freighter” the travel brochure had said. Another 11 days and we’d be home. It was Sunday; Mauritius and the Cape of Good Hope lay behind us; we were in the South Atlantic Ocean. I grabbed the silver fork and was about to poke it into that mouth-watering, appetizingly garnished salad, when my eyes noticed a multi-legged, brown something, struggling to free itself from the yellowish mayonnaise it was hopelessly stuck in. A live cockroach!

Lying on its back, it was caught in sticky, creamy substrate. Without telling my husband or alarming the other passengers, who were happily chatting and munching away, I succeeded in getting rid of the vermin and shoved it under the table. I tried to step on the menace and felt the crunch of its resistive cuticle through my bones, when my foot finally got hold of it. Never in my life have I killed a bug with such disgust and delight at the same time. I shuddered; it was over.

Now, I do well know that cockroaches, members of the ancient insect family known as Blattids, do not harm anyone. And I drew some comfort from the thought that these insects are not known to transmit diseases like, for instance, flies do, that they don’t sting like wasps, and that they don’t suck blood like mosquitoes. I had also been told earlier by my husband that most ships were said to have them and that even hospitals, chocolate factories and bakeries were usually not free of them. And yet – this ugly beast on my plate, in my mayonnaise, waving its thin and hairy legs at me, that was too much. I had thoroughly lost my appetite.

Manly and erect our handsome young steward rushed by to see if he could remove empty plates and unwanted dishes. Always attentive he noticed my lack of appetite and compassionately put it down to the stormy conditions outside and the rolling of our vessel. Perhaps there was a slight tone of mockery or mischievousness in his voice. Of course, even the best steward can overlook something, especially when it is a small, brown beetle-like insect covered in mayonnaise.

Nonetheless, from now on I became somewhat more critical and looked at our steward a little more carefully. Between meal times I was evaluating my observations. Curious – I was thinking had he perhaps got sloppier the closer the end of the trip drew near? He, who had always been so immaculately dressed and so well-groomed, wasn’t he often uncombed now when he served breakfast? His slender fingers, when they handed out the cutlery, did I not detect a touch of uncleanliness on them? And didn’t his fingernails look bitten and sometimes even outright dirty? I was supposed to look at the label, but couldn’t help focusing on the hand instead that held the bottle of “Riesling” when my glass was filled and I now thought I had found the answer, why our steward kept hiding his left hand behind his back when filling our glasses.

True, a hard-working steward, the powerful soapy water full of detergents, his daily dish washing and glass cleaning routines, that’s tough on one’s manicure and skin care. But his white shirts – it really seemed to me that he no longer was changing them every day and a stench of sweat seemed to be emitted from them when he passed by. And his beard: did he actually ever trim it? Did he even care? I wondered whether he brushed his teeth regularly.

I began to think I could smell his presence even if I did not see him. His witty remarks, his informative talk, nothing much behind it, I concluded. Mostly rehearsed platitudes, told a hundred times; shallow and stupid phrases made at the wrong time. Who knows, perhaps he even smoked secretly, drank in his cabin, took drugs. It was all possible.

The Bay of Biscay, another two or three days. By now I was convinced that I had never seen a more vulgar, filthy and uncaring person than this man, who called himself “Salon Steward”. Subconsciously, I worried whether I was perhaps doing him injustice and he wasn’t so bad after all. But then again, why was he so unpleasant, so irritating since he had placed the salad with the cockroach in front of me?

I decided I would not meet him any more and begged my husband to bring my food up to our cabin for the last two days. However, there on my own, I ate even less. I became weak and ill and in the British Channel thought I had to die. We reached Southampton just in time. One more day and I would surely not have made it alive.

Thus ended our once-in-a-lifetime 2 ½ month East Asia leg of the “Round-the-World” trip: a “relaxing experience for body and soul” – just like the travel brochure had promised.

© 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. 

How Small Can Small Be ?

A study of the eyes of miniature insects

In the year 2010, I published with my PhD-students S. Fischer and C. Müller in the journal “Visual Neuroscience” an article with the provocative title “How small can small be”. Although the article dealt with the compound eye of the parasitoid wasp Trichogramma evanescens, an insect of 0.4-mm total body length, the question of how small an animal or a part of it can be before it stops to function is of course an intriguing one. The smallest mammals are the Etruscan shrew and the bumblebee bat Craseonycteris thonglongyai; the smallest fish of just 1 cm total body size is Paedocypris progenetica, and the smallest frog and reptiles are Paedophryne sp. and dwarf geckos of 1 and 2 cm respective sizes.

Back to insect compound eyes. In 1975 I had examined the tiny eye of a beetle known as Corylophodes, whose total body size was below 1 mm. Compound eyes consist of a multitude of facets, each equipped with a small lens and a retinula, which contains a rod-like light-perceiving structure known as the rhabdom. It is obvious that for an eye of a given size sensitivity (related to the amount of light that can enter the facet) and spatial resolution (the amount of detail the eye can resolve) are in conflict with each other. Photography and camera-buffs know the relationship between aperture setting and exposure time: for high resolution you want a small aperture, but need more light (e.g. longer exposure).

If we take a look at the hemispherical eye of an insect and assume a constant facet diameter, increase of the eye would lead to an increase in sensitivity and resolution, because more facets would allow more light to be perceived and the angle between neighbouring facets would decrease, thereby improving resolution). But what about the situation in very small insects? They would have a problem, because a small head offers less space for big compound eyes. So, the facet size should be reduced, but there is a limit and a researcher named Barlow as long ago as 1952 calculated that smaller facets would be increasingly limited by diffraction. He concluded facet sizes below 10 µm would probably not occur. If facet sizes weren’t allowed to become reduced as the eye itself got smaller and saw its curvature increased, then the angles between neighbouring facets would become wider and resolving power would suffer. How tiny insects find a ‘compromise’ to solve this impasse is what interests us.

Another problem is that the rod-like rhabdom mentioned above acts like a light-guide in the bigger insect eyes, but as Alan Snyder 1979 worked out, effectiveness of a light-guide based on total inner reflection drops off as the diameter of the light guide gets smaller. With diameters below 1.5 µm light in the form of modes travels partly on the outside of the rhabdom, making it unavailable for the photo pigment in the rhabdom’s constituent membranes. Doekele Stavenga in the Netherlands showed that the fraction of the light conducted inside the rhabdom decreases with increasing wavelength for all modes. Thus, shorter wavelengths like blue, violet and UV would be the most useful for the tiny eyes of small insects. And yet, surprises still await the researcher: on the island of Hachijojima I caught a fly of 0.65 mm body length and examined its eyes with Dr Yumi Yamahama. Not only did this fly have three compound eyes (two lateral ones with 35 facets each and one dorsal eye with 90 facets on the top of its head), it also had an extremely shallow retinula and surprisingly thick lenses. We published the results in 2019 in the journal Entomologie Heute, but are still at a loss to explain how this miniature insect could be such a swift flyer, repeatedly being attracted to the light of my computer screen at midnight.

Finally, here’s a challenge: there are mini-snails with body lengths of 1mm or even less. I noticed they have black eyespots. How would their eyes be constructed and what could they possibly see with them?

© 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. 

biology zoology blog benno meyer rochow sneeze

The Science behind Sneezing

Have your handkerchief handy

Have you noticed that most of the words related to the “nose” start with the letters ‘n’ and ‘sn’? Apart from nose, nares, nostril, and nasal you’d find snot, snort, sniff, snuff, snore, snooze, snub-nosed and, of course, sneeze. The most common reason advanced for why people (and other animals) sneeze is that the act of sneezing removes an irritant or obstruction in the nasal passage. Suffering from hayfever (my children used to have fun chasing me around in the garden with flowers in their hands) I once counted that I was sneezing forty times in a row  – and that was not at all because of an obstruction in my nasal passages (or looking into the sun, which is said to trigger sneezing in some people). So, what goes on?

The allergic reaction to pollen like the one that made me sneeze is probably one of the commonest reasons of sneezing in humans. But it’s complicated, for it involves an oversensitivity reaction in which substance P (cf., my earlier blog) is increased in the nasal epithelium together with other neuropeptides like, for example, calcitonin (cf. also old blog). These and the release of antibodies and histamine by the body’s immune system to the perceived threat posed by the inhaled pollen, lead to the hypersensitivity reactions (e.g. nose and eye itch). All these in conjunction with neurotrophic factors stemming from the allergy, target neuronal fibres like chemo- and pain receptors and those sensing itch, which then send the information to the trigeminal ganglion. The trigeminal nerve that serves also the cheek and orbital region of the face then instructs the sneezing centre in the brain’s medulla to take action.

Action means that effector neurons should become active. Those involved with breathing make sure that deep inspirations occur prior to the sneeze and that the eyes and the glottis close, before through an increase of the pressure in the lungs the glottis suddenly opens and releases in an explosive action air and fluid droplets through mouth and nose. The pressures involved in a sneeze can be 176 mm Hg, which would be one tenth of the pressure of a tyre of a small car or one third of the pressure penguins generate to poop. During a sneeze thousands of tiny droplets of liquid are released up to a metre and sounds accompanying a sneeze can vary from faint to deafening.

People who own a dog or a cat know that their pets may occasionally sneeze spontaneously or when you tickle their nose or when they smell irritating chemicals. The same holds true for humans and I for one avoid the perfume sections of the department store because the odours there could make me sneeze. The sneezing that accompanies a cold is usually related to a mucus build-up in the nasal passages that the sneeze tries to remove. The Galapagos iguana and some marine birds sneeze to remove salt crystals that have accumulated in the nasal passage and need to be flushed out.  All vertebrate animals with lungs and a connection between the nose and the pharynx (that excludes the fish) are said to have ‘choanae’ (= internal nares) and can sneeze. The nose of a fish consists of two nasal openings for the inflow and two for the outflow of the water. Located between in and outflow nares is the olfactory epithelium with its odour sensitive cells. Thus, looking at the head of a fish you will see 4 nasal openings and not just two as in all terrestrial vertebrates. Sneezing in fish is therefore not possible.

Antarctica is a good place for people with pollen allergies. Although you can get cold there, you are not likely to ‘catch a cold’ there, but on one of my trips to the icy continent my friend and colleague Taka Hariyama sneezed (dust does exist in some areas of Antarctica). He sneezed once and seemed happy, exclaiming joyfully “only once!”. I was puzzled why he stressed “only once”, until I learned that ‘sneezing once’ suggests to a Japanese that someone is saying good things about the ‘sneezer’, but that sneezing twice means the opposite. Yet, what it means to sneeze 40 times in a row I don’t want to know.

© 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.