About Marine Insects

Insects account for over 75% of all species that have been described by science. Of the approximately 2 million described species, only about 30,000 or 3% are aquatic in any life stage. Rarer still are the 250 to 350 species that are routinely exposed to ocean or seawater. Despite low numbers, many insect orders have members that can survive exposure to ocean water. Although each order is represented by only a few species, the diversity indicates that numerous orders have independently evolved adaptations to salt water. The proportion of total species by insect order is shown in the chart below.

Orders not shown on chart

Thysanoptera 3%
Lepidoptera 1%
Other 1%

 

Despite their low numbers, marine insects still have a tremendous impact on man.

 

Flies are the most numerous and economically important species of marine insects.

However, their apparent dominance may be an artifact of their medical and social importance, or may reflect their ability as larvae to osmoregulate. Regardless of the reason, the disease-bearing mosquitoes, biting horse flies, deer flies, and midges have impeded the human development of millions of acres of coastal land.

mosquito.jpg - 11411 Bytes Here, a female Aedes sollicitans (now Ochlerotatus sollicitans) takes a meal. Mosquitoes vector a number of diseases including malaria and yellow fever which are fatal to man. Other marine flies (like sand flies) inflict painful bites and can transmit diseases such as leishmaniasis.

Marine insects include species of the open ocean (what are called pelagic species), species of tide pools (those in the intertidal zone),and beach and marsh swelling species (those regularly exposed to salt water from tides).

Of these habitats, the fewest insects are pelagic, and generally, the farther in shore, the greater the number of insect species. Let's look at these species in more detail.

Marine Habitats

As Far As the Eye Can Sea

oceancartoon.gif - 157288 Bytes The ocean may be the cradle of life, but that doesn't mean it's easy to live there. Underwater, organisms have to have a way to breath, must cope with salinity (which can draw water from their tissues), and survive the pressure from the water above them. On the surface, organisms face waves, dehydration, starvation, and need somewhere to lay eggs. Oh, and both places, other organisms are after your food and you.

There is a Tide in the Affairs of Insects

Tidal pools are continuously filled with sea water, but don't experience the extremes of the open ocean. However, the salt content in tidal pools varies, as water evaporates from the pool (making it saltier) and as the pool is refilled by the tides (making it less salty). tidepoolcartoon.gif - 184752 Bytes

Life is a Beach

Life on the seashore offers reliable places for oviposition... but, there are many problems to be overcome. First, shore dwelling insects must contend with constantly changing tides. Some insects avoid rising tides by surrounding themselves with air pockets, or by fleeing the rising waters.

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