Is there anyone who comes across a tunnel in the earth that doesn’t imagine the menagerie of fantastic beasts that could be lurking in its shadows?
From large woodland cavities that might be used by a badger to minuscule dots in a tree hosting a plethora of invertebrates, maybe even something that’s new to science?
No matter how long in the tooth you are, the ambiguity and mystery surrounding these mini voids is always enticing!
If you want such an encounter, any walk along the Wharfe that reveals a steep eroded river bank will likely reveal such an array of holes, you could be forgiven for thinking the army cadets use it as a shooting range.
Many of the visible holes are likely to be Sand Martin nests, with the odd chance of a Kingfisher nest who likes similar nest sites. But look a little closer (using binoculars during breeding season) and you might notice an innumerable amount of tiny holes scattered all over the banks. One of my favourite examples of this locally are the eroded banks opposite the weir in Burley in Wharfedale. For the last couple of years every September and October, I’ve made an effort to visit these grassy topped banks to observe a relatively new species to England and a particularly new species to Yorkshire! The Ivy Bee.
The Ivy Bee (Colletes hederae) is a solitary bee that was first officially recorded in Dorset, 2001. By 2014 this new arrival had “colonised” North Wales and went on to make its first notable appearance in Yorkshire in 2016.
In these modern times, the announcement of a new species can evoke the broadest of reactions: “Was it introduced?” “Is it an invasive species?” “What impact will it have on the existing native species?”.
From what anyone can tell it appears that the Ivy Bee arrived naturally from mainland Europe. Its unrelenting success is largely attributed to the fact it breeds late, after most other solitary bee species and feeding almost exclusively on (how did you guess?!) Ivy nectar.
In a presentation for the Biological Recording Company, post-doctoral researcher Aaron Bhambra suggests that the Ivy Bee may create the largest nesting aggregations in the world. Creating individual chambers off a main tunnel, the main tunnel can reach depths up to a metre into the terra firma. That’s on par with the neighbouring Sand Martin nesting tunnels!
I have spent the duration of my latest coffee considering what makes one species of bee more attractive than another, and I remain a little stumped. But the Ivy bee IS an undeniable stunner! I love the opportunity to photograph them on a sunny afternoon in late September to early October. Like with most wildlife observations, accessing one species will often open a gateway into a wider habitat and other species within it. Despite its late emergence, the Ivy Bee is no different. Flitting along and around the bank’s horizon a Small Copper (Lycaena phlaeas) butterfly restlessly manoeuvres, stopping occasionally and momentarily before getting itchy feet. Several Field Digger Wasps (Mellinus arvensis) appear to terrorise the area, bringing back prey items as food deposits for their nest chambers also in the banks. One wasp attempts to take a prey item into a tunnel already occupied by an Ivy Bee. A standoff ensues, the wasp tries backing in with its stinger but is also tentative, eventually the Ivy Bee flies off and the wasp enters the chamber with its prey. And then, just as the sun threatens to withdraw, one of my favourites appears. A ruby tailed wasp, (possibly Trichrysis cyanea) its metallic shimmer draws the eye instantly and it’s impossible not to fall for its charm.
So much intrigue, so much drama and so much joy, all from diving into a hole in the ground!