Acrossidius tasmaniae
In 3 days ~10% in a week ~20%
Acrossidius tasmaniae, the black-headed cockchafer or black-headed pasture cockchafer, also known as the Tasmanian grass grub, is a species of scarab beetle in the family Scarabaeidae. It is native to south-eastern Australia, occurring in Tasmania, Victoria, South Australia and New South Wales.
The species inhabits open grassy environments such as grasslands, pastures and lawns. Larvae feed on plant foliage and are considered an agricultural pest, causing severe damage to winter pastures and cereals when densely populated.
Acrossidius tasmaniae was introduced to New Zealand in the early 20th century, where it is regarded as a severe pest in dryland farming systems. The species has also been intercepted in Europe via international shipping. Despite its pest status, Acrossidius tasmaniae is an important food source for many species such as potoroid mammals, insectivorous birds, and parasitic wasps and flies.
Adult beetles are 9 to 14 mm long, and 4 to 5.5 mm wide. The body colour is variable, and can be yellow, brown, or black. Geographic variation is expressed in colour. Specimens in higher altitudes are often darker, while specimens from lower areas are... Wikipedia →
| # | Park | Country | Daily sighting probability |
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More parks will be added in future updates.
Rare
Under 5% of wildlife watchers report a Tasmanian Grass Grub sighting in Melbourne on a given day, based on 8 verified sightings from GBIF citizen-science data. It is the 670th most-seen of the 875 insects we can rate there. Over three days the chance rises to about 10%, and over a week to about 20%, if each day is a fresh chance.
February
In that month about 10% of wildlife watchers report a Tasmanian Grass Grub in Melbourne on a given day, against under 5% in March to January, the lowest months.
Among the best
Of the 2 cities where we can rate Tasmanian Grass Grub sightings, Melbourne ranks 2nd at under 5%, level with the leaders once rounded. The best odds are in Auckland (New Zealand, under 5%).
Same family: Scarabaeidae
The closest relatives of the Tasmanian Grass Grub that you can see in Melbourne (family Scarabaeidae, Scarabs) are Argentinian Scarab (about 20%), Cowboy Beetle (about 10%) and African Black Beetle (about 10%), with each one's daily chance of a sighting.
GBIF citizen-science records
It is estimated from how often the Tasmanian Grass Grub is recorded against all the insects logged in Melbourne (8 verified sightings), calibrated against known sighting rates. Figures are rounded to the nearest 10% because citizen-science data supports honest approximations, not decimals, and months with records from fewer than five people show "—". How it works.
