I was introduced to zazamushi (above) on a visit to Japan, and
found them delicious. Zazamushi are caddisfly larvae (usually Stenophylax marmorata) that live in
fast-flowing rivers, where they feed on material caught in their secreted silk nets [1]. Larvae are collected from the surface of rocks and then
cooked by frying in soy and mirin before being served, or canned for sale in
stores. I brought some back to the UK for friends to try and most liked them.
For some years, I worked on blackfly larvae that coat
sluices in enormous numbers (see above) - 1 million per square meter having
been recorded [2], although the larvae are small, varying in length from 0.2 -
0.9 cm, depending on their age. They form a monoculture of one species, Simulium noelleri, and could easily be
harvested and eaten. However, I was not tempted to eat any of the animals I was
studying, unlike Henry Gosse who experimented with cooking a few of the sea
anemones he was working on [3].
Part of my reticence came from a report from Dr Rory Post
who had eaten blackly larvae during his research on the insects [4]:
I decided that my own
understanding of this group might be advanced if I tasted a few larvae.
Selecting S. nitidifrons from a nice,
clean mountain stream in the Lake District I popped the tasty morsels into my
mouth and awaited enlightenment. All that came however was a certain loosening
of the bowels. Was this coincidence? The effect wore off within a day, and the
experiment was repeated, with similar effects. Determination of whether the effect
is caused by the larvae themselves or their own gut contents awaits further
experimentation.
We are not given comments as to taste, but Dr Post raises an
important point when it comes to the gut contents, as these reflect the whole range
of small particles suspended in the water column of the river, including mineral
particles, detritus, and many bacteria that may be pathogenic. Blackly larvae,
unlike net-spinning caddisfly larvae, do not select what they ingest and
anything that collects on the feeding head fans (see above) is ingested. This
makes for a poor quality diet and much of the total body mass of a blackfly
larva is made up of the gut and gut contents, with their feeding being near
continuous. If they were to be prepared for human consumption, each (of the thousands required for a meal) would have to be
deveined as one would do a prawn (shown in the video below)? Perhaps the answer
is to collect larvae in huge numbers and then allow them to feed in
channels supplied with finely-chopped herbs or something similar?
Although they are easy to collect, blackfly larvae are small
and there are clearly problems with their gut contents. Most aquatic insect
larvae are much more difficult to collect than blackfly larvae and zazamushi,
but adults of some groups that emerge from water in swarms are collected easily and are already utilised.
Adult female flies often contain fat reserves for the maturation of eggs and
there is little problem with gut contents since adults of both sexes feed on
plant sugars to give energy for flight, should this be needed. In addition to
nectar, the female adults of biting flies, like mosquitoes and blackflies also
require a blood meal (although some of the latter obtain enough food reserves
as larvae to not need to do so – S.
noelleri on "my" sluice
being one example). This may be a useful addition in terms of food value.
Adult aquatic insects are an important staple around lakes in Africa. As
described by Bergeron and colleagues [5], adult Chironomidae (non-biting
dancing midges), Chaoboridae (non-biting phantom midges) and Povilla sp. (a mayfly) -
..periodically swarm in immense
numbers along the shores and islands of Lake Victoria. The insects are
harvested, sun-dried, and ground into a flour for subsequent use. The insect
cake is prepared by mixing the flour with water and allowing the mixture to sun
dry.. ..the analysis of the insect flour revealed a high protein and low fat
content.. ..The high crude fibre content was a result of the chitin found in insects
[i.e. their skeletal components].. ..It can be noted that the flour was an
excellent source of niacin [Vitamin B3], thiamine [Vitamin B1] and riboflavin
[Vitamin B2].
Bergeron and colleagues [5] conclude their article by
stating:
The results of this research
demonstrate that aquatic insects which can be harvested in large quantities,
dried, and made into a flour have the potential to furnish substantial amounts
of high quality protein, vitamins and minerals to the diet..
There is clearly a huge potential in rearing both larvae and
adult aquatic insects more widely as food. Are there any entrepreneurs out
there willing to give it a try?
[2] Roger S. Wotton (1987) Lake outlet blackflies – the
dynamics of filter feeders at very high population densities. Holarctic Ecology 10:65-72.
[4] Rory Post (1981) ..and finally ... our culinary corner. Newsletter of the British Simulium Group
5:11.
[5] Donald Bergeron, Rodney J. Bushway, Franklin L. Roberts,
Irv Kornfield, John Okedi and Alfred A. Bushway (1988) The nutrient composition
of an insect flour sample from Lake Victoria, Uganda. Journal of Food Composition and Analysis 1: 371-377.
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