Garden Guides, Low-Flying Lawn Insects

Low-Flying Lawn Insects

21 September, 2017

Your lawn is a fitting habitat for many kinds of insects. It has countless hiding spaces for evading predators or ambushing unsuspecting ankles; it’s full of food for herbivorous and carnivorous insects; it’s an effective incubator of insect eggs, and it’s a cozy nursery for developing young bugs. Lawns harbor several low-flying insect species. Some are helpful, and others are pests.

Lawn Pests

Tiny, black and yellow frit flies lay eggs in a lawn, and their larvae feed on the turf. Small, dull-colored moths with snoutlike projections fly over lawn at dusk while depositing eggs. These eggs develop into sod webworms, which feed on the lawn, leaving brown patches. Insects that look like giant mosquitoes flying over your lawn are crane flies. The adults are harmless, but their larvae are common lawn-eating pests. Healthy lawns can tolerate frit flies, webworms and crane flies. If an infestation of crane flies and webworms is severe, then parasitic nematodes (Steinernema spp.) can be applied to the lawn to target both of the pests. Follow the product instructions for mixing and applying nematode treatments. Typical mixtures require mixing 1 teaspoon of the nematode concentrate in 1 gallon of water. Spray the lawn with the mixture while constantly shaking the sprayer to maintain an even distribution of nematodes. Keep the lawn moist for the next week for the nematodes’ full effectiveness.

Helpful Predators

Some insects fly low over a lawn to look for other insects to eat. Large, hairy scoliid wasps search a lawn for grubs on which to lay eggs. When the wasp eggs hatch, the larvae feed on grubs, helping to reduce the numbers of those pests. Smaller parasitic wasps target several kinds of soft-bodied lawn pests. Ladybugs, on the other hand, often fly over and live in lawns, where both their adult and larval forms feed on plant-eating aphids and other bugs. In order to maintain healthy populations of beneficial insects, avoid using insecticides on your lawn.

Biting Pests

Mosquitoes and biting midges, commonly called «no-see-ums,» are among the biting insects that fly low. Adult mosquitoes fly above and take shelter in a lawn and other foliage. Control lawn mosquitoes by removing all items that accumulate standing water; those items include birdbaths, toys, tires and gutters. Biting midges are less than 1/16 inch long and inflict a painful bite. Like mosquitoes, they breed in moist areas. Dressing in a long-sleeved shirt and long pants is the best defense against biting midges.

Harmless Lawn Bugs

Thrips — tiny insects with four fringed wings — often fly over lawns but do not damage them. You also may notice various fly species in your lawn, but they are not typically lawn pests or predators. When flying, they usually are searching for a food or egg-laying source, such as fallen fruit, animal droppings or small, dead animals.

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Corpse fauna

Many kinds of organisms live by feeding on dead bodies.

  • Updated 29/03/19
  • Read time 26 minutes
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In the process, their activities result in the decomposition of the body and the recycling of nutrients.

The dominant groups of organisms involved in decomposition are bacteria, flies, beetles, mites and moths. Other animals, mainly parasitoid wasps, predatory beetles and predatory flies, feed on the animals that feed on the corpse.

A dead body is therefore an ecosystem of its own, in which different fauna arrive and depart from the corpse at different times. The arrival time and growth rates of insects inhabiting corpses are used by forensic scientists to determine the circumstances surrounding suspicious deaths.

Bacteria

There are many forms of bacteria, which gain their energy in a variety of ways.

Some bacteria are autotrophic, making their own food in a similar way to plants by splitting carbon dioxide using energy from the sun, or through the oxidation of elements such as nitrogen and sulphur.

Bacteria involved in the decomposition of animal bodies are heterotrophic, breaking down complex molecules into their constituent elements through respiration or fermentation (depending on whether they are aerobic or anaerobic bacteria). Bacteria are largely responsible for the recycling of carbon, nitrogen and sulphur into forms where they can be taken up by plants.

For example, heterotrophic bacteria like Bacillus decompose proteins, releasing ammonia, which is oxidised by other bacteria into nitrogen dioxide, and eventually into nitrate. Nitrate can be assimilated by plants as a source of nitrogen.

There are many forms of bacteria, which gain their energy in a variety of ways.

Some bacteria are autotrophic, making their own food in a similar way to plants by splitting carbon dioxide using energy from the sun, or through the oxidation of elements such as nitrogen and sulphur.

Bacteria involved in the decomposition of animal bodies are heterotrophic, breaking down complex molecules into their constituent elements through respiration or fermentation (depending on whether they are aerobic or anaerobic bacteria). Bacteria are largely responsible for the recycling of carbon, nitrogen and sulphur into forms where they can be taken up by plants.

For example, heterotrophic bacteria like Bacillus decompose proteins, releasing ammonia, which is oxidised by other bacteria into nitrogen dioxide, and eventually into nitrate. Nitrate can be assimilated by plants as a source of nitrogen.

Flies

The larvae of flies (maggots) are the most obvious and abundant fauna present on corpses in the early stages of decomposition.

House flies Muscidae and blowflies Calliphoridae are the first to arrive (pioneer flies). Flies in both these families lay eggs (although some blowflies ‘lay’ larvae). The recently hatched larvae, as well as their parents, initially feed on the fluids that exude from the body. Later they enter the body through natural openings or wounds, and eventually feed over the whole body as the tissues decay.

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Different species of housefly and blowfly arrive at different times after death, and there can be considerable competition among flies for access to a corpse. Early arrivals, and flies which hatch faster, can gain a competitive advantage, although the flesh is easier to consume after it has undergone some decomposition. Flesh flies Sarcophagidae arrive slightly later than the other families, but they compensate for their late arrival by giving birth to larvae (maggots) rather than eggs. The succession of fauna that inhabit the corpse change its condition, making it suitable for succeeding fauna.

Juicy maggots provide an abundant food source for other animals, including other species of fly. The Blowfly, Chrysomya rufifacies, feeds on maggots of other flies as well as consuming decaying flesh. The larvae of Chrysomya are covered with protrusions called papillae, which serve as protection against the predatory attacks of other maggots.

When the corpse has dried out, two other groups of flies, the cheese flies Family Piophilidae and the coffin flies Family Phoridae join the beetles and mites in cleaning up the skeleton.

The Green-bottle, Lucilia cuprina, is a worldwide pest of sheep, imported to Australia from China. It is virtually identical to Lucilia sericata but occurs in drier areas. As well as laying in dead bodies and garbage tips, female Lucilia cuprina lay in parts of the fleeces of sheep that are contaminated with faeces and urine. The ammonia in urine is particularly attractive to the flies, and the young larvae can become established where the skin of the sheep has become irritated by the urine. These flies can then attack the living flesh of the sheep.

Lucilia cuprina is one of the first flies to lay its eggs in a corpse, and the larvae are of the smooth form.

The Green-bottle, Lucilia sericata, was introduced to Australia from Europe, and although it is virtually identical to Lucilia cuprina it only rarely attacks live sheep. It is also more coastal in its distribution, occurring in moister climates. Like Lucilia cuprina, it is one of the first visitors to a corpse, and the larval stages are smooth.

Calliphora stygia is a large brown blowfly that is common and annoying in houses, and features regularly in insecticide commercials. It is one of the earliest flies to visit a corpse and will also feed on living sheep provided that Lucilia cuprina has invaded the sheep’s tissues first. Unlike Lucilia, this species of blowfly is present throughout the year, and is able to exploit corpses during the cold months.

Chrysomia rufifacies is a large, metallic green blowfly whose larvae are predaceous, feeding on the larvae of earlier-arriving flies. Adult females do not lay their eggs in a corpse until the body is partially decomposed and maggots are available as prey. The larvae of Chrysomia rufifacies have tough spiny skin, which gives them protection against other predators. The larvae pupate on the surface, rather than burrowing into the soil, and they are particularly vulnerable to parasitism by wasps.

Flies lay eggs that are usually long and thin in shape, often resembling miniature rice grains. They are pale yellow or white in colour and usually laid in masses, although some species lay single eggs. In many species, females will lay up to 250 eggs in one sitting and can lay up to five clutches during their life.

Fly larvae — Maggots, First-instar. The larva, or maggot, is the main feeding stage of the fly. On hatching, first-instar larvae are roughly 2 mm long, growing to about 5 mm before shedding their skin.

Third-instar larvae grow to between 15 mm and 20 mm before wandering off as pre-pupae.

Maggot spiracles — The most distinctive feature for separating larvae of different instars is the structure of the posterior spiracles, though which the larvae respire.

The rear ends of maggots (fly larvae) consist of a chamber, in which their anus and posterior spiracles are located. (They also have anterior spiracles). Spiracles are used for breathing, and the possession of spiracles in a posterior location means that maggots can breath feeding 24 hours a day.

Hairy maggot, electron micrographs.

Mouth hooks of a maggot.

Fly pre-pupae and pupae After the third-instar larva has finished feeding, it moves around in search of a site in which to pupate. For many species, this involves burrowing into the soil. These late, third-instar larvae are called ‘pre-pupae’ and while they are searching, their skin starts to shorten, fatten and harden, ultimately becoming the pupal case, or puparium. Carrion fly puparia are brown or black oval structures, about 10 mm in length. Pre-adult flies spend around half their lives as pupae, and this is the stage during which the larval body becomes reorganised into an adult fly. Pupae are resistant to environmental extremes, and in many species, the fly will remain in the puparium until favourable conditions for emergence arise. In some species this means remaining in the puparium over the winter months. Emergence is triggered by environmental changes such as increasing temperature or a rainfall event.

Fly puparia — Corpse Fauna

House flies Family Muscidae

Adult house flies usually have spongy mouthparts and feed on fluids such as human perspiration or solid food that can be liquefied by the secretion of fly-saliva upon it. The larvae of many species of house fly are compost and/or dung feeders, although they can also feed on carrion.

The true House Fly, Musca domestica, has been transported world-wide by humans and although the adults are commonly observed feeding on exuded fluid from a corpse, the larvae are usually dung feeders. Adults are most common at corpses in the early stages of decomposition when the corpse is moist.

Another type of House fly, Australophyra rostrata, is attracted to corpses in the later stages of decomposition, after maggots of blowflies have disappeared, but before the corpse is fully dry. The maggots feed on the carrion, but they sometimes also prey on smooth maggots.

Flesh flies — Family Sarcophagidae

Flesh flies are stripey-backed or chequered flies, often with bright red eyes. They arrive at corpses slightly later than the pioneer blowflies, but the eggs hatch in the uterus of the female, before she lays them, with the result that the larvae are deposited directly on the body. This allows them to catch up on the blowflies, whose eggs take around 24 hours to hatch.

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Adult flesh flies still sometimes find themselves in competition with blowflies, as they fight for the best laying sites. When several flies attempt to lay in the same site, flesh flies can often be observed using their legs to kick other flies that stray too close.

Flesh fly pupae can remain dormant for long periods. Maggots of some Sarcophaga species hibernate as pupae in autumn and do not emerge as adult flies until late spring. Flesh flies often emerge in people’s houses after feeding on dead possums in their ceiling.

Flesh flies — Family Sarcophagidae

Flesh flies are stripey-backed or chequered flies, often with bright red eyes. They arrive at corpses slightly later than the pioneer blowflies, but the eggs hatch in the uterus of the female, before she lays them, with the result that the larvae are deposited directly on the body. This allows them to catch up on the blowflies, whose eggs take around 24 hours to hatch.

Adult flesh flies still sometimes find themselves in competition with blowflies, as they fight for the best laying sites. When several flies attempt to lay in the same site, flesh flies can often be observed using their legs to kick other flies that stray too close.

Flesh fly pupae can remain dormant for long periods. Maggots of some Sarcophaga species hibernate as pupae in autumn and do not emerge as adult flies until late spring. Flesh flies often emerge in people’s houses after feeding on dead possums in their ceiling.

Cheese flies — Family Piophilidae

Cheese flies are attracted to the cheesy odour which emanates from a corpse during the later stages of decomposition, particularly when the body is undergoing butyric fermentation. They are also common pests of cheeses and hams.

The Cheese Skipper, Piophila casei, has a worldwide distribution and is named after the behaviour of its maggots. When disturbed the larvae flex and release their bodies, skipping up to 15 cm into the air.

Although arriving after the bulk of the body has been consumed by the pioneer flies, cheese flies can occur in large numbers — 4,363 flies emerged from pupae derived from a single sheep’s head.

Cheese Skippers have been found in coffins buried up to 3 m deep and in corpses up to 10 years old.

Beetles

The first beetles arrive at a corpse soon after the body begins to putrefy. In contrast to the flies, beetles have chewing mouthparts and can manage tougher foods than the semi-liquid material that fly larvae are so efficient at exploiting.

Three types of beetle make their living out of corpses. The early arrivals tend to be predatory adults that feed on fly larvae. Some of these species lay their eggs in the corpse, and the emerging larvae, which share their parents’ powerful jaws, also feed on fly larvae. These species include the rove beetles (Staphylinidae), and hister beetles (Histeridae).

Late-arriving species tend to be specialist scavengers which feed on tougher parts like skin and tendons as the body dries out. The dominant late stage scavengers include the larvae of hide beetles (Dermestidae), and ham beetles (Cleridae).

Species such as the carrion beetles (Silphidae) are more variable in their diets. The adults are predatory, although they will eat some carrion, but their larvae are restricted to carrion on moist corpses.

Other families of beetles also eat carrion, for example, the carcass beetles (Trogidae), but they are minor players in the decomposition of corpses. In Australia, several dung beetles (Scarabaeini) are attracted to large carcasses, especially to the intestine of herbivorous mammals. These beetles have specialised, fluid-feeding mouthparts.

Beetles have a life cycle similar to the fly life cycle with egg, larval, pupal and adult stages. However, the number of instars (stage of development between moulting) in the larval stage varies between species from 2 up to 16, and the stages differ more from each other than the instars of fly larvae.

Rove beetles — Family Staphylinidae

Staphylinids are usually elongate beetles with small elytra (wing covers) and large jaws. Like other beetles inhabiting carrion, they have fast larval development with only three larval stages.

Devil’s Coach-horse Beetle, Creophilus erythrocephalus, is a common predator of carrion, and with its bright red head, is a very visible component of the fauna of corpses in Australia.

Adults are early visitors to a corpse and they feed on larvae of all species of fly, including predatory fly larvae. They lay their eggs in the corpse, and the emerging larvae are also predators. Creophilus erythrocephalus has a long development time in the egg, so it is common during the later stages of decomposition. As well as consuming maggots, they can also tear open the pupal cases of flies, so there is sufficient food to sustain them at a corpse for long periods.

Another rove beetle, Aleochara haemorrhoidalis feeds on eggs as well as young blowfly larvae.

Rove Beetle Aleochara haemorrhoidalis

Electron micrograph of a Rove Beetle

Wasp larva feeding on the fly pupa

Fly pupal case broken open to show wasp larva feeding on the fly pupa.

Histerids are usually shiny black or metallic-green beetles with introverted heads. Carrion-feeding forms generally hide under a corpse during the daylight, and only become active at night when they enter the maggot-infested part of the corpse to capture and devour maggots. Like other beetles inhabiting carrion, they have fast larval development with only two larval stages. Beetles of the genus Saprinus are among the first beetles to arrive at carrion. The adults feed on both the larvae and pupae of all species of blowfly, although they have a preference for fresh pupae. The adults lay their eggs in the corpse, and the larvae feed on blowfly pupae when they emerge.

Hister Beetle wrestling with a maggot.

Carrion beetles — Family Silphidae Silphids are large carrion beetles that feed on both carrion and fly larvae. Although they often hide under a carcass, they can sometimes be seen wandering around the carcass with a maggot in their jaws. Even though adults have been recorded feeding on carrion, they cannot survive on it alone, and die if they do not have access to maggots. Like other beetles inhabiting carrion, they have fast larval development. Ptomaphila perlata is a very common Australian carrion beetle found across the southern half of Australia. It has been found in a wide range of habitats including rainforest, woodland, heaths and even associated with beach-washed seabirds. Adults are frequently seen feeding on maggots but they have not been observed feeding on pupae. The larvae appear to be carrion feeders only.

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Hide beetles are some of the most important animals present in the final stages of decomposition of a carcass. The adults and larvae are not predaceous and feed on the dried skin, tendons and bone left by the fly larvae. Hide beetles are the only beetle with the enzymes necessary for breaking down keratin, a protein component of hair. Dermestes cadaverinus and Dermestes maculatus are two species occurring in Australia that are particularly common in summer. Both adults and larvae feed on dried skin ligaments and bone as well as dead insects. The larvae of both species are hairy.

Clerids are elongate beetles that often have a metallic sheen or are coloured red or yellow. Both the larvae and the adults are predatory, feeding on other insects. The Ham beetle, Necrobia ruficolis is found worldwide and is common in the later stages of decomposition of a carcass. The larvae feed on dried fat and pupate inside the empty pupal cases of flies, after sealing the opening with silk.

Carcass beetles are large beetles with very thick exoskeletons and uniform dark colouration. They are among the last beetles to inhabit a carcass and, they feed on dried remains such as skin and ligaments. Both adults and larvae feed on the carcass and the larvae live in vertical burrows underneath it when they are not foraging. Australian carcass beetles are particularly common in the more arid parts of Australia. Omorgus candidus is typical of carcass beetles found at vertebrate carcasses in Australia.

Beetle larvae are more variable in form than fly larvae, and there is more variation between species in the number of larval instars (stage of development between moulting) — up to fourteen. Beetles associated with carrion live in an ephemeral environment and tend to have short larval development times with only two or three instars. Most beetle larvae have chewing mouthparts (like most of their parents)* and they feed on a variety of foods associated with corpses. Some are specialist predators, feeding on fly larvae, while others feed on dry flesh, skin, ligaments and hair. *Adult dung beetles (Scarabaeini) have liquid feeding mouthparts and are attracted to particularly large juicy carcasses.

australianmuseum.net.au

The 4 Stages of the Firefly Life Cycle

  • B.A., Political Science, Rutgers University

Fireflies, also known as lightning bugs, are part of the beetle family (Lampyridae), in the order Coleoptera. There are about 2,000 species of fireflies worldwide, with over 150 species in the U.S. and Canada. Like all beetles, fireflies undergo complete metamorphosis with four stages in their life cycle: egg, larva, pupa, and adult.

Egg (Embryonic Stage)

The firefly life cycle begins with an egg. In midsummer, mated females will deposit about 100 spherical eggs, singly or in clusters, in the soil or near the soil surface. Fireflies prefer moist soils and will often choose to place their eggs under mulch or leaf litter, where the soil is less likely to dry out. Some fireflies will deposit eggs on vegetation rather than directly in the soil. Firefly eggs usually hatch in three to four weeks.

The eggs of some lightning bugs are bioluminescent, and you may see them glowing dimly if you’re lucky enough to find them in the soil.

Larva (Larval Stage)

As with many beetles, lightning bug larvae look somewhat wormlike. The dorsal segments are flattened and extend to the back and sides, like overlapping plates. Firefly larvae produce light and are sometimes called glowworms.

Firefly larvae usually live in the soil. At night, they hunt slugs, snails, worms, and other insects. When it captures prey, the larva will inject its unfortunate victim with digestive enzymes to immobilize it and liquefy its remains.

Larvae emerge from their eggs in late summer and live through the winter before pupating in the spring. In some species, the larval stage lasts well over a year, with the larvae living through two winters before pupating. As it grows, the larva will repeatedly molt to shed its exoskeleton, replacing it with a larger cuticle each time. Just before pupating, the firefly larva measures about three-quarters of an inch in length.

Pupa (Pupal Stage)

When the larva is ready to pupate—usually in late spring—it constructs a mud chamber in the soil and settles inside it. In some species, the larva attaches itself to a tree’s bark, hanging upside down by the hind end, and pupates while suspended (similar to a caterpillar).

Regardless of which position the larva assumes for pupation, a remarkable transformation takes place during the pupal stage. In a process called histolysis, the larva’s body is broken down, and special groups of transformative cells are activated. These cell groups, called histoblasts, trigger biochemical processes that transform the insect from a larva into its adult form. When the metamorphosis is complete, the adult firefly is ready to emerge, usually about 10 days to several weeks after pupation.

Adult (Imaginal Stage)

When the adult firefly finally emerges, it has only one real purpose: to reproduce. Fireflies flash to find a mate, using a species-specific pattern to locate compatible individuals of the opposite sex. Typically, the male flies low to the ground, flashing a signal with the light organ on its abdomen, and a female resting on vegetation returns the male’s communiqué. By repeating this exchange, the male homes in on her, after which, they mate.

Not all fireflies feed as adults—some simply mate, produce offspring, and die. But when adults do feed, they are usually predacious and hunt other insects. Female fireflies sometimes use a bit of trickery to lure males of other species closer and then eat them. Not much is known about firefly eating habits, however, and it is thought that some fireflies may feed on pollen or nectar.

www.thoughtco.com

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