Scaphinotus angusticollis (narrow-collared snail-eating beetle)

Scaphinotus angusticollis    Family: Carabidaea

Common name: narrow-collared snail-eating beetle; 
narrow-collar snail-eating beetle

Food: snails; slugs; earthworms; spiders; insects; berries
Adult size: 1.5 – 2 inches (4-5 cm)

Type: Beneficial

Life cycle phases: 
                  Generation: 1 over a year and a half
                  Egg: laid in May – June
                  Larva: about 1 year
                  Pupa: about 2 months
                  Adult: 4 – 5 months


Description & Life cycle:
Entire beetle is black. Almond-shaped abdomen has an overlaying rosy-purple matte luster. The pronotum is rather heart-shaped and ridged on both sides. Head and prothorax are long and narrow. Underlip is deeply notched. Antennae are long and slender with 5th segment and beyond covered with short hairs. Long legs raise the body up from the ground.

Eggs are laid under debris in May through June. After hatching, larvae actively feed on slug and snail eggs, as well as earthworms and other insects. Larvae overwinter in soil. Pupation occurs when soil warms up in spring. Adults appear in June and are active through into September, largely at night.


Special Notes:
This is a nocturnal beetle native to southern regions of British Columbia to northern portion of California, mostly west of the BC Coast Range mountains and the Cascades but also on the eastern slopes of the foothills. There is a black form found almost exclusively on Vancouver Island. Preferred habitat is moist forest areas, usually under logs and other debris. Feeds on slugs, snails, earthworms, spiders, earth-dwelling insects and berries. Narrow head and prothorax allow this beetle to reach inside the curved shell of a snail to pull it out.


Remedial Action:
None. This beneficial insect is to be encouraged into our gardens.

 

Posted on August 12, 2020

Harpaphe haydeniana (cyanide millipede)

Harpaphe haydeniana      Family: Xystodesmidae

Common name: cyanide millipede; almond-scented millipede; yellow-spotted millipede

Food: leaf litter; conifer needles

 Adult size: 1.5 – 2 in (4-5 cm) long

Type: Beneficial

Life cycle: 
            Generations per year: 2 – 5
            Egg: > 3 weeks
            Instar: unknown
            Adult: 2 – 3 years

 

Description & Life Cycle: Adult cyanide millipedes are quite distinct with their black colouring and bright yellow patches along both sides. The body consists of about 20 segments with males having 30 pairs of legs and females having 31 pairs.

Millipedes are oviparous (egg-laying) and mating begins in spring. Cyanide millipede females will lay anywhere from 30 to 300 eggs in a season, typically underneath a rotten tree or log. The young hatch into an immobile dupoid in three weeks or more. The dupoid then molts into a pale-coloured instar stage. Each subsequent instar molt produces another segment which is slightly darker until it reaches maturity and is fully black with its yellow patches on the side. Adults live for 2 to 3 years.

 

Special Notes: Harpaphe haydeniana is native to the Pacific Northwest from southeast Alaska to California and west as far as the Sierra Nevada Mountains. The adult millipedes play an important part in maintaining the health of the forest ecosystem by breaking down the leaf litter and releasing nutrients for other organisms through their digestive system. The immature millipedes feed on humus.

This millipede has few predators due to its ability to exude hydrogen cyanide through its exoskeleton. This secretion is relatively harmless to humans, although it may cause some skin irritation so be forewarned. If possible, wash affected area immediately with soap and water. A more extreme reaction will occur if any secretion should get into the eyes. Seek medical aid if this occurs. Small-sized pets…cats and dogs…may exhibit stronger reactions to the hydrogen cyanide if it should get into their eyes. Rinse with water immediately, if possible, and seek veterinary aid.

 

Remedial Actions: This insect is highly beneficial to the health of the forest ecosystem so no remedial action is needed. In fact, they should be respected and left to do the work they are meant to do. Unfortunately, in just one week, we have seen two Harpaphe haydeniana which had been stepped on and killed in our local forest.

 

Posted on July 15, 2020

 

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

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