Wildfile Q & A: What makes the holes in Alligator Flag Leaves?

alligator flag rolls

Q: What makes the orderly slits and holes in Alligator Flag leaves?

alligator flag rolls

A: The culprits are caterpillars.

When new leaves of the Alligator Flag (Thalia geniculata) first emerge, the leaflets are tightly rolled.

Once the leaves approach their mature length, they begin to unfurl. That’s why there are rarely small and large leaves on the same Alligator Flag plant.

Brazilian Skipper butterflies use Alligator Flag as their larval host plant, which means eggs are laid and caterpillars hatch. When the caterpillar feeds on a new, still-rolled leaf, it  bores through the leaf. Then the leaf unfurls and … voilá! There is a neat pattern of orderly little geometric holes in the leaf.

To make a comparison that’s easy to relate to, think back to making a chain of paper dolls or making snowflakes from a sheet of paper by folding the paper several times and making a few cuts with a scissors.

Unfold the paper and a nice chain of dolls or snowflake-like symmetrical pattern magically appears.

Nature just uses leaves and caterpillars instead of paper and scissors.

By Dick Brewer


Wildfile Q& A: What do butterflies and other insects do when it rains, and where do they go?

Ruddy Daggerwing butterfly resting under a leaf

Q: What do butterflies and other insects do when it rains, and where do they go?

Ruddy Daggerwing butterfly resting under a leaf
Ruddy Daggerwing butterfly resting under a leaf by Dick Brewer
Where insects go when it rains depends on how much rain falls and on the species of insect.
If the rain is light enough, many insects stay out and are unaffected.
If the rain is moderate, most insects adapt and seek shelter. Butterflies and many other insects find spots under flowers, leaves, branches, or other vegetation, cling to the spot, and use it like an umbrella. If they are small enough, they may take shelter in a bark crevice.

If the rain is heavy, insects that are more accustomed to dry land will cling to whatever shelter they can find. The heavier the rain, the more substantial shelter they seek so they are not knocked into the water. Even if they are dislodged, it is uncommon for insects to
drown because of heavy rain. Most are just displaced and then find themselves in new surroundings.

Small burrowing insects such as ants find air pockets in underground burrows, even during flooding and flowing water. They require very little oxygen and can survive for weeks using air pockets that are always available even in densely flooded areas.
Insects that frequent water more often, like water beetles and mosquitoes, can negotiate rising, flooding and flowing water with more ease and they simply go with the flow.
                                     -Dick Brewer

Wildfile Q& A: Do all spiders bite, and are they poisonous?

shoreline spider
shoreline spider
Shoreline Fishing Spider (Dolomedes triton) By Dick Brewer


Q: Do all spiders bite, and are they poisonous?

A: There are two problems with this question: a technicality, and a set of false assumptions.

First, the technicality. “Poisonous” and “venomous” are two different things. No spider is poisonous — harmful to eat, breathe, or touch. Mushrooms are sometimes poisonous, but spiders are not. Spiders are venomous; their toxins are proteins which only work when injected.

Second, all spiders do bite, but most local spiders are harmless because they are not aggressive and will not bite indiscriminately, or their fangs are simply too small to nip through our comparatively thick skin. Just because they are venomous does not mean they are
dangerous to people.

Spider venom does not exist to harm creatures which are too large for spiders to eat, like humans. The purpose of spider venom is to subdue the spider’s prey, almost always insects. In brief, it’s an insecticide.

Nevertheless, all larger spiders with a body length of a half inch or more should be treated with caution. Avoid flicking them away from your body. People allergic to bee stings may react more strongly to the bite of a spider than an ordinary person.

Bees and wasps kill more people in the United States in one year than spiders and snakes combined kill in ten years, and dogs and cats kill or injure more people each year than bees and wasps. Yet most people like dogs and cats and fear spiders and snakes.

For More Information: http://www.iflscience.com/brain/why-are-we-afraid-spiders


By Dick Brewer


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