Species of the week: pantaloon bee (and Digger Alley friends)

Yes folks, it's that time of year again. Digger Alley is open for business, and the usual guests are already arriving and putting on a show.

For those not in the know, Digger Alley is a stretch of the visitor trail that cuts through the North Bushes between the pond and North Wall. The passage of feet over the years has eroded the sandy path so that it now sits a few centimetres below the adjacent scrubby area, leaving a low sandy, south-facing bank along the edge of the path. The south-facing aspect is important as it creates a warmer microclimate, and this has attracted a variety of burrowing insects that make their homes directly below the feet of our visitors!

The most well known residents of Digger Alley are our bee-wolves, which even starred on the BBC's One Show last year. These are predatory wasps that specialise in catching honeybees. Barely bigger than the bee, they carry it slung beneath their body back to their burrow. Then comes the really exciting bit (or gruesome, depending on your viewpoint). The paralysed bee is "stored" up to a metre below ground in a nesting chamber where it becomes food for the developing beewolf larva. Sadly we don't get to watch that bit, but it's exciting enough just watching the beewolves antics above ground. I went to spy on them for the first time this year during my lunchbreak yesterday.

A beewolf in Digger Alley today

Beewolf is one of the 70 species to spot at Minsmere, but I have featured them in my weekly species of the week blogs last year, so this time the spotlight falls on another of the residents of Digger Alley: the pantaloon bee. When our volunteers first referred to pantaloon bees we all laughed, and comedian Bill Bailey's Twitter followers didn't believe him either when he saw them a few years ago, but this is what they are actually called. Or, least, it is one of the commonly used alternatives to the official English name of hairy-legged mining bee. Pantaloon bee is definitely sexier.

A pantaloon bee

The paddle-shaped hind legs, which look remarkably like a pair of baggy trousers, or pantaloons, are used for excavating their burrows. Unlike the beewolfs, they are not taking live food into their nests. Instead, like most bees, they collect pollen which they store for their larvae, and when they return from foraging on nearby flowers their hind legs can be covered in bright yellow pollen, as in the photo below.

There are other residents in Digger Alley too. One of the easiest to identify is the tiny green-eyed flower bee. Despite their small size, and incredible speed, these lovely bees are easily located by the distinctive buzz as they pass by. They are also mining bees, and were very active in Digger Alley yesterday, but I also found several feeding along the nearby North Wall. They seem to be attracted to both bird's-foot trefoil and greater  knapweed, along with honeybees and red-tailed bumblebees.

Green-eyed flower bee on knapweed

The knapweed also proved popular today with meadow brown butterflies and another distinctive bee: the pointy-bum bee, or steely-vented sharp-tailed bee.

Back in Digger Alley, the ruby-tailed wasps, or jewel wasps as they also called, seem to be particularly numerous this year. These tiny, colourful wasps are parasites. They are looking for the larvae of other mining bees and wasps, including beewolfs, in which they will lay their eggs to feed their own young. As a result, they hang around the burrow entrances, waiting for the incumbent insects to leave before dashing inside themselves.

A ruby-tailed wasp

Other digger wasps to look for include the ornate-tailed wasp (that catches small bees), sand-tailed wasp, or weevil wolf (that catches weevils) and the distinctive sand wasp (that catches green caterpillars). Digger Alley is also home to other tiny black wasps, various flies, and the lovely dune chafer beetle, so it well worth spending some time checking out the insects here. Don't forget to bring your macro lens for the camera - or simply use a mobile phone for some great macro photos.

Elsewhere on the reserve, there was great excitement at the discovery of a dark green fritillary butterfly close to the Whin Hill watchpoint on Saturday morning. This is a very rare butterfly in Suffolk, with the nearest breeding colony at Winterton on the Norfolk coast, and is almost certainly the first Minsmere record. One lucky visitor even managed to get a photo, allowing us to confirm the ID. It's not been sighted again since, though there was a brief sighting of an unidentified fritillary in the same area yesterday.

Dark green fritillary by David Pitt

There are many other butterflies to be seen too. Small heaths seem to be particularly numerous on Whin Heath this year, and all three of our skippers are now on the wing - the near identical small and Essex skippers and the fractionally bigger large skipper. The grassy areas also attract common blue, meadow brown, ringlet and small copper. Look out for white admiral on flowering bramble bushes (especially along the Woodland Trail), and purple hairstreak in the top of the oak canopy, or head to Westleton heath to spot the rare silver-studded blue.

The numbers and variety of dragonflies are increasing too. At the end of my walk yesterday, I asked two visitors what they were watching in a low tree and there, posing long enough for me to grab some photos, were a freshly emerged brown hawker alongside it's Norfolk cousin. This was a great chance to compare our two large brown dragonflies, one with yellowish wings and the other with green eyes.

Brown hawker (above) and Norfolk hawker (below)

Of course, with all these insects to look at, it would have been easy to miss any birds flying over, but I struck lucky twice when looking up as I walked through the North Bushes. First, a bittern flew over, heading to North Marsh, then a hobby dashed past in pursuit of dragonflies. I also enjoyed a few minutes watching the sand martin colony, where one of our volunteer guides pointed out a grass snake lurking in the reeds along the edge of the pond.

The bittern was just one of five species of heron seen at Minsmere yesterday, with four spoonbills and a great white egret feeding on the North Levels, where they could be watched distantly from Whin Hill, as well as the more predictable grey heron and little egret.

Other sightings from the Whin Hill/Island Mere are included great crested grebe and mute swan on the mere, common terns and an adult little gull feeding in reedbed pools, whitethroats and green woodpeckers around Whin Hill itself, plus singing reed and sedge warblers and reed buntings around the mere. The Savi's warbler was hear again a few times yesterday, too, and I even heard our resident tawny owl hooting in the afternoon sunshine!

Although I didn't head out to the Scrape myself, sightings there included Mediterranean gulls, kittiwakes, common terns, avocets, spotted redshanks, black-tailed godwits, teals, shovelers and a couple of pairs of oystercatchers with chicks.