librarian2003 (librarian2003) wrote in weagardening, @ 2008-06-13 23:47:00 |
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Current mood: | bouncy |
Entry tags: | birds, enemies, friends, insects, wildlife |
Week 8 - Garden Wildlife Part One
We've looked at Pests and Diseases this week. One thing we've seen is that it's easy to confuse friends and enemies.
So, here's a bonus handout with some extra information about friends, enemies, and those that are somewhere inbetween.
GARDENING FOR PLEASURE
Garden Wildlife
Friends
Peacock Butterfly: Inachis io
The Peacock Butterfly is easily recognised with the striking eyespot markings on its wings, designed to frighten predators. Males and females are similar in markings, but the female is slightly larger. The underside of the wing is dead-leaf brown. There is one generation in a year. The males are territorial, setting up their patch at the edge of wooded areas when they emerge from hibernation in the spring. They see off rival males and pursue passing females. After mating the eggs are laid on stinging nettles where they hatch into black, spiny caterpillars. By May the adults from the previous year have died off. The caterpillars of the new generation pupate in July and the new adults emerge shortly after. They can be seen sipping on the nectar of many plants, especially Buddleja, Hebe and Sedum. In September they go into hibernation to avoid the winter weather.
Red Admiral Butterfly: Vanessa atalanta
The Red Admiral is a migrant, from Southern Europe and North Africa from May onwards. The name is a corruption of 'admirable', due to their bright colours. Some overwinter so there can be sightings all year round, but the largest numbers are seen in late summer and early autumn. Some fly south, a few hibernate, but most die off in the cold weather. The males and females both have similar patterns on their wings, but the females are usually slightly larger. The undersides of the hindwing have a mottled pattern which helps to conceal it as it roosts. They feed on nectar from many flowers including Buddleia, Sedum, Clover and Hebe, or they can be seen on rotting fruit. The early arrivals lay eggs and the nearly black caterpillars are about 35mm in length with yellow spots along their sides, and have hairy spines. These develop over the summer and pupate to produce a later generation in the autumn.
Small Tortoiseshell Butterfly: Aglais urticae
The Small Tortoiseshell is one of the commonest British butterflies easily recognised with its bright orange and black wings, and the edge of D-shaped blue spots on the fore and hindwings. The pattern on the forewing could be mistaken for that of the Painted Lady Butterfly, but the latter is larger and does not have the blue spots. As with most butterflies the male is smaller than the female. The adults emerge in the spring and seek out a food source where the males defend a territory, but they will move on after a few hours if no mate shows up. When a female is encountered there follows a chase which ends with them mating. The eggs are laid on stinging nettles. The caterpillars are black with yellow lines along the body and hairy spines which give some protection from predators. They metamorphose into a chrysalis, which can often be found hanging under a window sill. Some adults may emerge prematurely during mild periods in the winter. The majority are seen from March to June and the new generation, from mid-July to late September when they can be seen feeding on Budleja, Thistles and other nectar-rich flowers as they stock up for winter hibernation. The numbers of the Small Tortoise have fallen by as much as 80% in the last 20 years in parts of the British Isles. This is thought to be due to a parasitic fly which has moved here from southern Europe. First recorded in 1999, the Sturmia Bella Fly lays its eggs in the butterfly caterpillars. Adult flies emerge from the chrysalis.
Painted Lady Butterfly: Cynthia cardui
The Painted Lady is distributed worldwide, but the ones found here are migrants arriving from Southern Europe and North Africa from late April onwards. They can have up to three generations from June to October when they migrate southwards in swarms. Any remaining perish in the cold weather. The female lays eggs on thistles, nettles and a few other plants where the caterpillars go through several instars as they feed on the host plant. They are grey or black with yellow stripes along the side and they draw the leaves together with silk as protection.
Buff-tailed Bumblebee: Bombus terrestris
There are about 19 species of bee in Britain and the Buff-tailed Bumblebee is the largest. They live in colonies of up to 150, but only fertilised young queens survive the winter as they do not make enough honey to see them through the cold season. Their ability to sting is of concern to most people, but they are not as aggressive as honey-bees and the drones (males) do not have a sting at all. They will only sting under if duress, but do not lose the sting and die if they do (as with Honeybees).
Badgers dig out the nest to eat the honey and larvae. Also numbers are reduced if the Cuckoo Bumblebee targets the nest. The female either replaces the queen or sneaks in and lays her eggs for the host workers to tend. They can dislocate the muscles from the wings and exercise the muscles to generate heat, so they are one of only a few insects that can regulate their body temperature.
Red-tailed Bumblebee: Bombus lapidarius
The Red-tailed Bumblebee is nearly all black with an orange-red coloured tail. Like the more common Bombus terrestris, it lives in a colony of about 100 to 200. The queen is the largest member of the colony and the workers are much smaller with early ones about the size of a house fly, although they have similar colouring. The nest is usually under large stones or in dry-stone walls. They have a relatively short tongue and prefer to land on the flower to feed rather than on the wing. After winter hibernation the queen seeks out a suitable nesting site and starts a new colony with the fertilized eggs she is carrying - feeding them with nectar and pollen placed in pots made from wax. The first brood of female workers are infertile and emerge to raise further broods from the remaining eggs the queen continues to lay, feeding them on pollen and nectar which they bring to the nest. Later broods have males which can collect nectar, but do not have pollen baskets - they have tufts of yellow hairs on the head and upper body. Near the end of the season they leave to find females from other colonies to mate. Only fertilized females hibernate and the males are not permitted back into the nest so they soon die, as do the workers and old queen when the first frosts occur. As with B. terrestris there is a Cuckoo Bumblebee which targets the Red-tailed Bumblebee by laying eggs in place of the host.
Hover Flies
Hover flies are in the Family of insects known as Syrphidae with just two wings like all the true flies. Most other flying insects have four. The adults feed mainly on nectar and pollen, and can be seen among the flower borders hovering near to the blossoms. There are many species and some have striking markings resembling wasps and bees, possibly to deter predators. The larvae feed on aphids and other plant-sucking insects such as thrips. The female lays her eggs singly near to the sucking pests and the larvae hatch a few days later and are fully developed after about three weeks. The pupal stage which follows lasts for a further two to three weeks depending on the external conditions. There can be several generations throughout the year, but the final generation overwinters as pupae mainly in the soil before emerging the following spring. There is some commercial use of hover flies as a biological control of aphids with the added bonus of aiding pollination as the adults feed.
Common Darter Dragonfly: Sympetrum striolatum
The Common Darter Dragonfly is one of the shorter species of dragonfly found in the British Isles. They can be seen between mid June and October, often basking on a warm surface. The adults feed on smaller insects such as the midges which annoy us gardeners as we do our work. They breed in still ponds and sheltered lakes. The larvae live around the marginal vegetation feeding on tiny water creatures and remain in the water for a year.
Ground Beetle
These shiny, blackish brown beetles have well developed mandibles. Adults and larvae are both carniverous, preying on worms, slugs, insects, and adult New Zealand Flatworms. They spend most of their time on or under the ground and hunt mainly at night, some climb into trees, shrubs, and crop plants to hunt. Ground beetles are often found in houses in the spring. They may crawl around basements or ground floor rooms or fly to bright lights, but are not known to bite people. Female ground beetles lay eggs in the soil. Eggs hatch into larvae that feed in or upon the soil under debris. Depending on the species, there may be several generations per year. Both adults and larvae are beneficial because they feed on larvae of harmful insects. Vine Weevil has a similar shape but is about half the size of a ground beetle.
Devil's Coach-horse: Staphylinus olens
A Rove Beetle distinguished by having short elytra or wing covers, although they do not fly. They are found in and around decaying material, feeding on fly larvae and other insects. It is a useful predator, most active at night, especially of adult New Zealand Flatworms and Slugs. When disturbed they adopt a threatening scorpion-like posture raising their rear end and opening their jaws. The abdomen releases a foul-smelling substance. It does not sting, but can give a painful bite.
Common Centipede: Lithobius forficatus
Centipedes are totally carnivorous, feeding on live insects and other small animals. They do not damage plants. They may bite if crushed, causing some pain and swelling. A natural predator of vine weevil eggs and grubs, so leave them alone!
They overwinter as adults and lay eggs during the warm months. Usually eggs are laid in the soil and are protected by adults. A few species give birth to living young.
Sexton Beetle: Nicrophorus investigator
The Sexton or Burying Beetle got its name from the fact that the adults bury the corpses of small mammals and birds to feed their larvae. The genera name comes from a misspelling of the Greek "necro" which is the stem of many words relating to death. The male and female take part in the burial by excavating the soil below the body and the animal sinks into the ground. They also have a rather unique parental caring role among invertebrates by staying with the larvae to protect, and help them to feed. There are six species of Sexton Beetle in the UK, five of which have the black and orange wing cases. They fly well and are said to be able to scent a dead body up to two miles away. When the burial is complete - a process which can take up to 8 hours - the adults strip off the fur or feathers. As they do this they coat the carcass with secretions which slow the decay processes and prevent the odour from attracting other animals. The female then lays the eggs in the soil nearby where they hatch after a few days. The larvae are able to feed on their own but, to speed their development the parents digest the flesh and regurgitate the liquidised food. If there are too many larvae for the size of the carcass the parents may reduce the number to suit. Also if the carcass is large a number of adult pairs may co-operate in the burial and share it to raise their offspring together. The larval stage lasts for several days then they move off into the nearby soil where they pupate.
Dung Beetle
Most dung beetles are small and nocturnal, but the larger Common Dor Beetles (Geotrupes spp.) and the Minotaur Beetle (Typhaeus typhoeus) are more easily seen. They are members of the Family Scarabaeidae. Dung beetles are important because they get rid of a lot of animal faeces, breaking it down and incorporating it into the soil, so helping in the recycling of nutrients. This also makes the world a less smelly place to live in and reduces the numbers of other insects like flies which would otherwise breed in it. In the UK dung beetles utilise the dung of cows, horses, rabbits, deer and sheep. A pair dig a tunnel beneath a cowpat and drag as much dung as they can down into it. The females normally stay in the burrow, using their long broad legs to build numerous galleries in the soil. Dung is deposited in each gallery and an egg is laid in the dung, providing the emerging grub with nourishment. The males provide the dung pellets for the female to bury. Dung is mostly composed of half digested grass and a smelly liquid portion, and this is what the adults feed on, some of them have specialised mouth parts designed to let them suck out this nutritious soup; it is full of micro-organisms which the beetles can digest.
Dung beetles are often referred to as 'Scarabs' hence the classification Scaraboidea, and in ancient Egypt the scarab or dung beetle was their most important religious symbol.
Cinnabar Moth: Tyria jacobaeae
The Cinnabar Moth is quite common in the British Isles and flies at dawn and the early evening as well as at night. There is one generation per year, appearing from May to July. It usually rests during the middle of the day on low vegetation, but flutters off if disturbed, showing its bright colours which make it easy to spot. The red patches on its black fore-wings and the all red hind-wings give rise to the name - coming from the red mineral, cinnabar. The bright colour is also a warning to predators that it is one of the most poisonous insects around. After mating the eggs are laid on Ragwort and related plants - but Ragwort is the main food source. The toxins in the leaves do not harm the caterpillars, but protect them, making them poisonous and unpleasant tasting. Other plants sometimes eaten are Groundsel and Coltsfoot. The caterpillars are also cannibalistic which is not always caused by a lack of food, although a large infestation can strip the plants of their foliage. They have bright yellow and black stripes running around their slightly hairy body. Although native to Europe and central Asia, it has been introduced to North America, Australia and New Zealand as a biological control for Ragwort.
Red Ants: (Myrmica rubra group of species )
The Red Ant is one of the commonest and there are eight species of them here. Colonies of 100 to 300 can be found under stones and paving or sometimes rotting tree trunks, in most gardens. Their sting is the piercing type and can be painful. Red Ants prefer sweet food like nectar or the honeydew secreted by Aphids. When they find a food source they lay a trail of pheromone back to the nest and regurgitate some of the food as in indicator when they communicate with the other workers there. Some species of ants 'herd' aphids to ensure a ready supply of honeydew.
Also the Myrmica species are known to tend the larvae of Blue Butterflies whose caterpillars secrete a few drops of sweet liquid which causes the ants to take them into the nest where they feed on the ant larvae. The majority of members of a colony are sterile female workers, but some of the eggs develop into males (drones) whose only purpose is to mate with the new queens. In the late summer these males and future queens develop wings in order to mate. The queen dies after up to 15 years of a productive life, and the colony dies out.
Treatments
Ants are not usually a problem and can live quite happily in the garden without causing too much damage. They can make mounds of soil as they excavate their nest, but this can be brushed away. If disturbed they will defend their territory and give some stings, but usually this is just a mild irritation. If they are giving you aggravation there are many ways to discourage or remove them. Here are a few:-
Do not leave uncovered food around where it will attract them, especially if eating outdoors.
Locate the entrance of a nest and place an upturned pot over it - use a clay pot which will not be blown away. After a few days the ants will have migrated to the surface with their white larvae and they can be swept up.
Place the legs of an outdoor table in containers of water to act as a moat which the ants cannot cross.
Boric acid is toxic to ants and many other insects as it attacks their nervous system and causes dehydration so a 50:50 mixture with icing sugar makes a bait which will be taken to the nest where it should destroy the colony. It is an ingredient in many commercial products and has been used for centuries as an insecticide, a flame retardant, an antiseptic and in food preservation, so it is relatively non-toxic to humans and their environment. The nest can be located by following the returning ants, or quite often it is found while working in the garden when a stone is turned over.
They do not like peppermint so place it where you don't want them to go, or at their nest. Peppermint extract in water can be applied to surfaces.
If an ant is squashed clean the spot well as the corpse will release pheromones which will attract others. It is best to use a vacuum cleaner to remove unwanted ants.
A circle of petroleum jelly around the entry point will halt their journey, and if bait is placed within the circle they will take it back to the nest.
Another deterrent is ground cinnamon which can be sprinkled around to keep them out.
Instant coffee placed at the entrance of a nest and repeated a few times will see them off.
Diatomaceous Earth could be described as a biological control although the active agent is no longer alive since it is the fossilised remains of diatoms - tiny algae. It works by sticking to the exoskeleton of the ant by electrostatic attraction and abrades it as it moves around resulting in holes which lead to dehydration and death. It is applied as a fine powder to paths and around nest openings.
Grits, (a cereal favoured in the Southern States of USA), causes the ant to swell up and die. Not readily available here, grits are prepared by soaking ground maize in an alkaline solution like bicarbonate of soda. Try porridge instead.
There are a number of branded products available to destroy them or act as a repellent.
(continued)