Araneus trifolium (pumpkin spider)

Araneus trifolium - pumpkin spider

Araneus trifolium          Family: Araneidae
(uh-RAY-nee-us  tri-fohl-EE-um)
Common name: pumpkin orb weaver spider; shamrock orb weaver spider
Adult size: 
excluding legs: 0.8 inches (2 cm)
including legs: 1.5 – 1.75 inches (3.8 – 4.5 cm)
Life cycle: one generation per year
Type: beneficial   

 

pumpkin spider - frontal close up

Description: Abdomen colour of the pumpkin spider is variable…white, yellow, orange or brown. No matter the colour, there is a smattering of small white dots marking their back and several dark round indentations. Another distinct identifying feature are the white and brown bands on their legs. They also have bristles running the length of each leg, as well as a third claw on their “foot” which helps them manipulate their silk as they are weaving and to walk across their web. These spiders have the trademark number of eight eyes…two rows of four…but their vision is surprisingly poor.

pumpkin spider building bowerFemales are quite a bit larger than males, as is typical in other spider species. The abdomen of the female is spherical growing larger as she nears time to lay her eggs. Come mid-September, the female lays anywhere from several hundred to a thousand eggs in one or more egg sacs or cocoons, roughly 3 cm (1.2 inches) wide. These cocoons are often called a bower, or a retreat, and can be found roughly one metre (39 inches) off the ground…typically made up of seed heads or grass strands woven together with the spider’s silk. The female will guard her eggs until the winter temperatures eventually drop low enough to kill her. The eggs over-winter in their bower and tiny spiderlings emerge in spring. Each spiderling is capable of spinning a tiny replica of its parents’ web.

Pumpkin spiders prey on insects, usually paralysing whatever gets caught in their web with a toxic bite and then wrapping it for eating it later. If the insect is itself venomous, the pumpkin spider will wrap it first and then paralyse it with its bite.

 

Special Notes: Native throughout much of North America. They are not often seen in spring due to their small size upon hatching. However, as they grow, particularly the larger females, they are spotted more frequently in late summer and autumn. Beneficial insect for pest control.

While the pumpkin spider’s bite is toxic to insects, it is rarely of consequence to humans. The exception is those people who have more sensitive immune systems or sensitive skin.

 

In our Zone 7a garden: The cross orb weaver spider, Araneus diadematus, is much more common in our garden but every now and again a pumpkin spider appears sometime in August. Most recently, a female appeared at our compost bins mid-August 2017. She, or another female pumpkin spider built a bower in a few strands of our silver maiden grass, Miscanthus sinensis var. canadensis ‘Cosmopolitan’ in the second week of September. The female remained on guard of her eggs until the first week of October when the temperatures dipped to 0.5 °C (32.9 °F) and -1.0 °C (30.2 °F) two nights in a row.

pumpkin spider gathering grass strands for her bower

 

 

pregnant pumpkin spider guarding her bower

 

 

 

 

 

 

Note: The camera lens cap next to the female pumpkin spider gives some representation to her size. The lens cap is 2 inches (5.2 cm) across.

pumpkin spider size comparison

 

Posted on October 11, 2018

Dolichovespula maculata (bald-faced hornet)

bald-faced hornet in Scrophularia auriculata flower

Dolichovespula maculata             Family: Vespidae
Common name: Bald-faced hornet

Host plant: various species

Adult size: 0.5 – 0.75 in (13 – 20 mm)

Beneficial predator


Life cycle:
           Generations per year: 5 – 7 depending on latitude
            Egg: 6 days
            Larva: 8 days
            Pupa: 9 – 10 days
            Adult: 122 – 170 days depending on latitude

 

Description & Life Cycle: The bald-faced hornet is not a hornet, but rather one of the many types of yellowjackets. They are black and white in colour versus the typical black and yellow of other yellowjackets which likely attributes to their being called a hornet. Notably, their face is white which explains the “bald face” in their name. Bald-faced hornets are larger than their yellowjacket counterparts.

Inseminated (fertilized) queens are the only ones to overwinter, emerging anywhere from the end of March in central California to mid-May in Washington State and southern British Columbia, Canada. The lower the latitude the longer the life cycle; the higher the latitude the shorter the lifecycle.

bald-faced hornet workersThe overwintered queen builds a nest out of wood cellulose she has gathered, chewed and mixed with her saliva to produce a paper-like material. Once a few brood cells have been formed inside the nest, she lays her first batch of eggs. The queen tends and feeds this first group of emerging larvae who will become workers and assume the chores of expanding the nest, collecting food, feeding the young larvae, and protecting the nest upon their maturity. (Photo right: 2 worker hornets: worker top left is building onto the nest; worker right is returning from a hunt to feed young larvae.)

Towards the end of summer, the queen will lay eggs destined to become future queens. She will also lay unfertilized eggs from which males, called drones, will emerge. Once mature, the new queens and males will leave the nest to mate. These queens will feed on nectar before searching out a suitable spot to overwinter in tree hollows, under bark, in rock walls, and even attics.

The new young queens are the only survivors. The rest of the colony, including the current queen, will perish when the first frost of winter hits.

 

Special Notes: Called a hornet, but not a hornet, this bee species is actually an “aerial yellowjacket”…one of about 8 species in the genus Dolichovespula. Exclusively native to North America, it is found in all Canadian provinces and territories, except Nunavit, as well as in all American states, with the exception of Hawaii.

This bee species is a social insect and lives in colonies of up to about 400 bees. Bald-faced hornets have a distinct caste system made up of:

  • Queens – fertile, egg-laying females; she is the largest in the colony
  • Workers – infertile females who continue nest building, tending young, collect food, and defend the colony from interlopers / invasion
  • Drones – fertile males (from unfertilized eggs) whose sole purpose is to mate with future queens; they do not have stingers

The grey, paper-like nests are typically large, pear-shaped structures tapering to a narrow entry point at the bottom. They can be up to 23 inches (58.5 cm) in length and 14 – 15 inches (35.5 – 38 cm) in diameter. They are usually built in trees and large shrubs but have been found near homes and other human structures which have flower gardens nearby.

Bald-faced hornets feed on nectar for quick energy but are wonderful hunters of insects which makes this bee a welcome beneficial insect to anyone’s garden…although they do not distinguish between good insect and pest insect when they are hunting.

 

large bald-faced hornets' nest In our Zone 7a garden: We have yet to see a nest colony in our garden, but did spot a large nest in a neighbour’s tree one block over from us. Wherever the bald-faced hornets make their annual home, we can always guarantee they will show up in our garden to hunt insects and feast on flower nectar, particularly from the Scrophularia auriculata ‘Variegata’ plants. These plants, commonly called variegated water figwort, are sited right at the entrance to what was once my herb garden…a point of entry which is much used in the course of a day spent working in the garden. Truthfully, we have brushed right up against the branches where many of these hornets have been feeding on nectar, and have yet to be stung. This gives credence to the claim bald-faced hornets are generally docile unless their nest is disturbed. In that case, it is best that you run. Fast.

Because of their docile nature, and the fact this bee does so much good work in the garden for us, assisting in keeping the pest insects under control, it is highly recommended you do not destroy their nests or kill the bees. Unless of course, they have built a nest in an unfavourable location on your house.

 

Posted on April 11, 2018

 

Celastrina echo echo (western spring azure butterfly)

 

Western spring azure butterfly - female Celastrina echo echo
Common
name: western spring azure
Family:
 Lycaenidae
Subfamily: Polyommatinae

Host plant: Flowers of shrubs & trees, such as chestnut, blackberry, Prunus (cherry), maple, oak, Cornus (dogwood), Lonicera (honeysuckle) 

Adult size: wingspan: 1 – 1¼ inches (2.5 – 3.2 cm)

Type: Beneficial

Life cycle: 
            Generations per year: two, maybe more
            Egg: hatch in 4 – 8 days
            Larva: unknown
            Pupa: unknown
            Adult: a few days

 

Western spring azure - female - wing undersideDescription & Life Cycle: Upper-side of wings on male is a violet blue colour outlined with a thin line of black against the narrow outer marginal band of white. Female is a more muted violet blue colour with smoke-grey colouring inside the thin white margin on both the forewing and hindwing. Female also has an added uniform row of smoke-grey spots along the bottom edge of the hindwing. Summer form of female has mostly white with slight smoke-grey overtones and a blush of violet blue on the hindwing. Underside of wings on both male and female is a whitish smoke-grey colour with a pattern of dark spots which can range from faint to clearly defined. There are slight variations in colouring of both sexes through each successive generation.

Not much is really known about the life cycle of the western spring azure butterfly, other than it overwinters in the chrysalis stage.

The larvae probably go through four to five instar stages with the colouring of the latter stages being either white, cream, green, or pinkish with darker stripes on its back and sides and covered in very fine hairs. It will be slug-shaped and predominantly found on flowers or flower buds. Ants could be in the vicinity as they have a symbiotic relationship with the larvae of the western spring azure. They stimulate the larvae to produce a drop of honeydew from the seventh segment on their back. The ants, in turn, remain with the larvae to deter marauding parasitic wasps and flies from laying their eggs on the larvae.

 

Special Notes: Celastrina echo subsp. echo is a unique species of western spring azures to BC, including Vancouver Island. This subspecies varies in colouring slightly from the species, Celastrina echo

Western spring azure butterflies are often found in open deciduous woodlands and gardens filled with shrubs. Tend to avoid vast open areas. This is typically the first butterfly species to appear in early spring…anywhere from the middle of March into April, depending on weather. Males tend to congregate at puddles or edge of streams, sometimes in large numbers. Once mated, females lay their eggs singly in flowers or flower buds on a wide range of host plants. Both sexes die shortly after mating and egg laying.

After eggs have hatched, the larvae will feed on the flowers of the host plant. They rarely eat the leaves.

When larvae are ready to pupate, they drop to the ground and search for a concealed spot, or crevice. The smooth, oval-shaped chrysalis is a light brown or brownish-yellow colour with notable black markings.

This is a common butterfly species with no conservation concerns.

 

 

Posted on April 28, 2017

 

 

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