[Illustration: FIG. 21.]
Of all the evils to which bee flesh is heir, there can hardly be any so
terrible as the effects of the parasite _Stylops_ on the species of
_Andrena_ and _Halictus_ which it attacks. This very extraordinary
creature, which is now considered to be a beetle, lives during the early
stages of both sexes in the body of the bee, which it enters when the bee
is in the larval state. Its head protrudes like a minute flat seed between
the body segments (fig. 21), and so is visible externally, but the rest of
the creature, which is a grub-like larva, rests amongst the intestines of
the bee; the female matures in the bee's body and never leaves it. The
male, however, when mature, escapes, leaving the {78} [Illustration: FIG.
22. Stylops larva in abdominal cavity: after Perez.] great hole which he
inhabited open; he is provided with wings, and I have more than once caught
one flying in the open--but to return to our afflicted bee. This may be
attacked in either sex, and by one to five of the parasites. I have
specimens myself with four parasites in them, and a case of five has been
recorded. Mr. R. C. L. Perkins, writing on this subject, says: "On removing
the integument dorsally from the bee, the large body of the female parasite
will be seen lying above the viscera, often almost entirely concealing
them". If this is the condition of a bee nourishing only one parasite, I
must leave it to my readers to imagine the state of the poor wretch who is
supporting five! The outward appearance of one with several parasites is
generally much distorted; the abdomen is very much inflated, and the poor
creature is unable to fly any {79} distance, and can only crawl about, or
perhaps take short flights of a foot or so. The effects, however, seem to
be very different in different cases. I have caught _Andrenas_ with two
_Stylops_ in them, flying about as usual and apparently none the worse for
their inmates. Probably the position the parasite occupies may make a great
difference in its effects on the bee.
The most notable effect produced by _Stylops_ is the alteration in the
structure and colour of certain of the bee's characteristic features. In
_Andrena_ the males differ very considerably from the females both in form
and colouring. They have no pollen-brushes on their legs, and in some few
species the face above the mouth is white, whereas in the female it is
black. Now the effect of the parasite seems to be to unsex as it were its
victims so far as their outward appearance is concerned. This is no doubt
due to the internal effects it has on the larva of the bee. Anyhow, if a
female is attacked, in most cases the pollen-brush is much reduced, the
face tends to become more hairy, and, if it be the female of a white-faced
male, spots of white are often produced on the face. On the other hand,
{80} if it be a male subject, the hairiness of the face is diminished, the
white colour is often reduced or absent, and the hairiness of the legs is
increased.
Before the effects of the parasite were recognized, several new species
were described simply on specimens of unusual appearance in consequence of
its presence.
These effects, however, like the effects produced on the activity of the
bee, vary exceedingly in extent. On some the parasite seems to have no
effect, in others the alteration in appearance is very great. This, again,
is probably due to the position of the parasites and to the pressure they
exert on the reproductive organs of the body in the larval state.
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