As mentioned in last week’s blog, beetles are the largest group of insects in the world – if we delve a little deeper, we find the largest group of beetles is the weevil – there about 97,000 kinds of these tiny critters (typically 0.25 inches / 6 mm) – so I guess you could say that the weevil is the most successful creature on earth!
Whilst they may be small, they can rustle up a speed of 5 miles per hour; some can fly, whilst others are earth-bound. Typically, they only live 3 to 4 months and so their top priority in life is finding a mate and reproducing – although some do manage to lay eggs without needing to mate first! As well as furthering the next generation, the weevils’ other main raison d’etre is eating!
Indeed, the name weevil does tend to conjure up images of tiny mites munching their way through your favourite food and a quick internet search returns numerous pages on all the problems weevil’s cause and what a nuisance they are considered to be.
Do weevils deserve their dodgy reputation? It’s definitely hard to find a fan and there are many weevils who are confirmed pests; examples include wheat, vine, rice and maize weevils (no prizes for guessing what they like to consume!) and boll weevils, who’s preferred dinner is cotton crops.
What makes them so efficient at getting their way through foodstuffs? They have a long snout, called a rostrum, which contains their chewing equipment – hence their nickname of snout beetles. This appendage helps them to burrow their mouths into their food effectively – making them highly efficient eaters, which is bad news if they’re on your crops or infiltrating your pantry! Another use for their snouts is for boring holes in which to lay their eggs.
It’s not just our food they have a liking for either – weevils feed on certain pine trees, introducing a fungus, which blocks the frees’ resin flow and ultimately can cause its demise – this adversely impacts the health of the forest, as groups of dead trees can be a fire hazard.
But are all weevils pests? Like all creatures, whilst they might not be on our list of favourites, they form a vital part of a variety of ecosystems – weevils are an important food source for many other animals such as birds, insects, frogs and even hedgehogs.
When it comes down to it, weevils are just going about their business of munching plant matter – unfortunately, this brings them into conflict with humans, as their chosen dinner menu does tend to be our crops and foodstuffs. The battle rages on between us and the weevils – with many and various ways of control, aside from chemicals, there is biological control in the form of nematodes; as well as physical barriers and even manual removal.
Whilst unfortunately these critters have a taste for our farm and garden produce, their passion for plant consumption has been used to advantage, in helping to control incursive plant species. An example of this is the use of the seedhead and root weevil to help reduce spotted knapweed plants in North America – so poacher turned gamekeeper!
Indeed, when highly invasive water hyacinths were proving a menace in Lake Victoria, Africa, by reducing fish numbers, getting caught up in power generating turbines and providing a habitat for malaria carrying mosquitos – to the rescue comes the neochetina weevil, who was introduced to take down these pesky plants – so you see, not all weevils are truly bad!
Whatever you think of them – and as far as I can see, the overwhelming opinion is one of dislike at best and downright hatred at worst – you have to give it to them, after all, they are the most successful creatures on the planet…