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A Biological Arms Race in birds
has resulted in sophisticated defences against Cuckoos.
Parasitic birds such as cuckoos lay eggs that mimic those of
their hosts in an effort to trick them into accepting the alien
egg and raising the cuckoo chick as one of their own. New
research has found that different bird species parasitised by
the
African Cuckoo Finch have evolved different
evolved
strategies to fight back
The most frequent host of the Cuckoo Finch is
the Tawny Flanked Prinia and they have developed a strategy
where every host female will lay a different type of egg with
colour and pattern varying greatly among nests. These egg
‘signatures’ make it harder for the cuckoo to lay accurate
forgeries and her chances of laying a matching egg are
exasperatingly low and the Prinia parent recognises that the egg
in the nest is that of a cuckoo and proceed to eject it by
spearing it on the end of her beak and carrying it away.
Box Jellyfish may seem like rather simple
creatures, but in fact their visual system is anything
but. They’ve got no fewer than 24 eyes of four different kinds.
Now researchers have evidence revealing that four of those eyes
always peer up out of the water, regardless of the way the rest
of the animal is orientated. What’s
 more
it appears that those eyes allow the jellies to navigate their
way around the mangrove swamps in which they live.
It is a surprise that a jellyfish – an animal
normally considered to be lacking both brain and advanced
behaviour – is able to perform visually guided navigation, which
is not a trivial behavioural task. This shows that behavioural
abilities of simple animals, like jellyfish, may be
underestimated.
Gazing into the depths of a pond, it’s hard to
miss the insects that whirl and zip beneath the surface.
However, only one species of spider has joined them; the diving
bell spider
Argyroneta aquaqtica.
These spiders spend their entire lives under
water, only venturing to the surface to replenish their diving
bell air supply.
Until recently, it was not known how long the
spiders could remain under water before the bubbles oxygen level
dropped, and they would have to rush to the
surface to renew the supply. It was thought that they would have
to make the journey several times a day. Recent research however
has shown that the diving bell acts like a gill, sucking
oxygen from the water, and that the spiders
only need to dash to the surface once a day to supplement their
air supply.
The spiders spend their entire lives
submerged and even lay their eggs in their diving bells. Another
problem for the spiders is that the bubble continually shrinks
because nitrogen diffuses back into the water, eventually
forcing the occupant to venture to the surface to re-supply the
diving bell. Despite this, researchers were surprised to find
that the spiders could sit tight for more than a day. It is
advantageous for the spider to stay still for a long time, not
only to protect themselves from predators, but also so they
don’t alert potential prey that come near.
A pod of Bottlenose Dolphins was seen off
Nare Head near the Lizard on the 4th of May. A pod of 4 or 5
Bottlenose Dolphins was seen off the Wherrytown Rocks Newlyn
late morning on the 27th. They were watched as they headed
toward Newlyn Harbour Mouth then on toward Roskilly. Late
afternoon they were watched as they played with a Grey Seal
below the NCI Lookout at Cape Cornwall. Early afternoon a pod of
unidentified dolphins was seen off Porthcurno, these were almost
certainly the Bottlenose seen earlier at Newlyn and later at
Cape Cornwall.
Another Grey Seal was seen off Cape Cornwall on
the 9th. 2 Harbour Porpoises were seen off Sennen on the 7th.
Single Basking Sharks were seen off Lizard Point, Porthcurno and
Porth Ledden and a pair were seen off Porthcurno on the
18th.
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