pollen-masses and thus to fertilise them. I
find from experiments find from experiments 1861 1866 1869 1872 |
have, also, reason to believe 1859 1860 |
that humble-bees are
almost indispensable almost indispensable 1861 1866 1869 1872 | indispensable 1859 1860 |
to the fertilisation of the heartsease (Viola tricolor), for other bees do not visit this flower. ↑1 blocks not present in 1861 1866 1869 1872; present in 1859 1860 | From experiments which I have tried,
I have found that the visits of bees,
if not indispensable, are at least highly beneficial to
the fertilisation of our
clovers;
but humble-bees alone visit the common
red clover (Trifolium pratense), as other bees cannot reach the nectar.
|
I have also found that the visits of bees are necessary for the fertilisation of some kinds of clover: for instance, 20 heads of Dutch clover (Trifolium repens) yielded 2,290
seeds, seeds, 1866 1869 1872 | seeds; 1861 |
but 20 other heads protected from bees produced not one. Again, 100 heads of red clover (T. pratense)
produced produced 1866 1869 1872 | pro- duced 1861 |
2,700 seeds, but the same number of protected heads produced not a single seed. Humble-bees alone visit red clover, as other bees cannot reach the nectar. It has been suggested that moths may
serve to serve to 1861 1866 | serve to 1869 1872 |
fertilise the clovers; but I doubt
this this 1861 1866 |
whether they could do so 1869 1872 |
in the case of the red clover, from their weight
being apparently not being apparently not 1861 1866 |
not being 1869 1872 |
sufficient to depress the
wing-petals. wing-petals. 1861 1866 1869 | wing petals. 1872 |
Hence
we may infer as highly probable we may infer as highly probable 1861 1866 1869 1872 |
I have very little doubt, 1859 1860 |
that, that, 1866 1869 1872 | that 1859 1860 1861 |
if the whole genus of humble-bees became extinct or very rare in England, the heartsease and red clover would become very rare, or wholly disappear. The number of humble-bees in any district depends in a great
degree degree 1859 1860 1861 1866 1869 | measure 1872 |
on the number of field-mice, which destroy their combs and nests; and
Col. Col. 1866 1869 1872 | Mr. H. 1859 1860 1861 |
Newman, who has long attended to the habits of humble-bees, believes that "more than
two-thirds two-thirds 1860 1861 1866 1869 1872 |
two thirds of 1859 |
of them of them 1860 1861 1866 1869 1872 | them 1859 |
are thus destroyed all over England." Now the number of mice is largely dependent, as every one knows, on the number of cats; and
Col. Newman Col. Newman 1866 1872 | Mr. Newman 1859 1860 1861 | Col.Newman 1869 |
says, "Near villages and small towns I have found the nests of humble-bees more numerous than elsewhere, which I attribute to the
number number 1859 1860 1861 1866 1872 | numbe 1869 |
of of 1859 1860 1861 1866 1872 | r of 1869 |
cats that destroy the mice." Hence it is quite credible that the presence of a feline animal in large numbers in a district might determine, through the intervention first of mice and then of bees, the frequency of certain flowers in that district! |