Even before the recent storms there were signs of the changing season. Flushes of red berries had begun to appear in roadside hedges and subtle colour changes were permeating leaf canopies. One sign for me, though, that always heralds the arrival of autumn is the emergence of the ivy bees (Colletes hederae), the last species of solitary bee to appear in this country. It’s the time of year when I stand in front of clumps of flowering ivy gazing at these insects feasting on this final flush of food. So, here are two stories about my recent experiences with the ivy bees.
The first concerns a visit I made to Roundham Head, Paignton, south Devon in the second week of September:
Hidden away on one side of a residential street on Roundham Head is a curious area of rough grass and trees divided into rectangular spaces by old stone walls and loved nowadays by dog walkers. This was once the kitchen garden of a nearby Victorian villa, now a care home, set in a commanding position on the edge of the promontory overlooking Torbay. The kitchen garden is surplus to requirements but the land has not been developed and the old walls have been commandeered by ivy. At this time of year, this normally dark green and slightly sinister climber adopts a new persona covering itself with lime green globe flower heads creating a multi-sensory experience for anyone prepared to look.
I approach one of the old stone walls bathed in sunshine, and gradually I become aware of the sickly-sweet perfume emanating from the ivy flowers to pervade the surrounding air. This perfume attracts huge numbers of insects which move about the ivy flowers in all directions at high speed, occasionally pausing on a flower to sample the extraordinary, late-season canteen of pollen and nectar. This profusion of insect life means that a clearly audible buzz surrounds the ivy.
Today, I see honeybees, hoverflies, a speckled wood butterfly and a buff tailed bumblebee together with many, many ivy bees. These insects must have emerged very recently and with their pale chestnut-haired thorax and yellow and black-hooped abdomen they look very fresh. The slimmer, slighter males (about two thirds the size of a honeybee) outnumber the chunkier females who collect lumps of bright yellow pollen on their back legs. The pulsating movement of so many insects implies a huge kinetic energy fuelled by the sugary nectar provided by the ivy flowers.
Wherever there is ivy and sunshine there are ivy bees on the old walls and the same is true when I walk through the nearby public gardens built on the cliffs overlooking Goodrington Sands. The gentle microenvironment offered by this seaside garden supports succulents, palms and other tender plants and today the agapanthus are providing flashes of a bright steely blue. Ivy has also insinuated its way into the gardens growing along old walls and railings overlooking the sea.
At one end of the gardens is a partly concealed path leading downwards to the beach below and along one side of the path I find a long grassy bank. The grass has not been cut this summer, a result of the pandemic, but beneath the grass cover I can see bare red soil with open holes and many more male ivy bees. This is the main nest site for the ivy bees at Roundham Head. The males are even more excited here, dancing above the grass, flying backwards and forwards rapidly and from side to side in a tick tock movement. They occasionally explore the holes but emerge disappointed and fly off. Sometimes there is a little joshing between the males who seem overexcited but they are waiting for females to emerge so that they can mate.
Today, though, I don’t witness any matings but I do see a few females returning to the nest area carrying bright yellow pollen so some couplings have occurred. These mated females enter the nest holes and leave pollen as food for their larvae. It does feel, however, as though the main emergence of female ivy bees has not yet occurred here. The males will go on waiting by the nest site for that chance to mate, visiting the ivy occasionally for a top up of sugary nectar.
My second story comes from a visit we made to West Sussex in the third week of September to deliver our daughter to University. We had a few days walking in the county including this visit to the coast:
Autumn had arrived with a vengeance in West Sussex, the temperature had dropped by nearly ten degrees overnight and there were heavy squally showers at West Wittering where we had planned to walk. Rain fell as we made our way along quiet lanes between houses to access the track along the water’s edge leading to East Head a huge sand spit projecting into Chichester Harbour. Long views across the flat watery surroundings made approaching storms easy to spot adding an elemental feel to the day. East Head is coated in marram grass which must help to stabilise its structure but, as we walked along the beach, there were signs of erosion at the sides of the spit and much of it is cordoned off to prevent further damage. Near the tip, it was possible to look at plants growing away from the edge such as sea holly, its prickly blue flowers faded to grey, sea rocket with its pale violet flowers and sea spurge its grey green leaf-covered stems tipped with greenish yellow complex flowers.
Behind East Head is a lagoon with salt marshes and the path along this side eventually curves round to meet shingle beaches on the edge of the harbour. Oaks grew along the edge and a few generous clumps of ivy overhung the beach. Much was in flower and here I saw the first ivy bees of the day, all males with clear yellow and black hoops moving backwards and forwards with high speed despite the lack of sun.
This kind of watery environment with extensive salt marshes should also favour the close relative of the ivy bee, the rare Colletes halophilus which Steven Falk refers to as the sea aster bee owing to its preference for the flower. I looked around for sea aster and found some, rather pale and faded but I saw no insects on the flowers. Then we came to a grassy open area by the side of the water. Large stands of gorse were growing by the edge and one of these was smothered by Russian vine, an invasive scrambling climber with many racemes of small white flowers. I have seen this used by ivy bees in Devon, even when flowering ivy is abundant and the same was true here, or so I thought. Insects that looked like ivy bee males were moving about the flowers rapidly, barely resting to feed but I managed a few photos as it was otherwise difficult to see the details of the insects. In the photos, to my surprise, all of the bees I captured on camera had black and white hoops.
The sea aster bee looks very similar to the ivy bee only its hoops are white compared to the ivy bee’s yellow hoops. So, could I have seen the rare sea aster bee here? The environment is certainly right for the insect and it has been recorded at this site before but it is impossible to draw a firm conclusion based on colouration. Male ivy bees can fade, losing their yellow colour and microscopic analysis of the mouth parts is required to distinguish males of the two species unequivocally but that is beyond my capability.
Females are easier to distinguish from photographs as there are yellow furry patches, like epaulettes, at the top of the abdomen of the ivy bee that are lacking in the sea aster bee. You can see these furry patches in the picture of the ivy bee at the end of this post. Unfortunately, I saw no females that day but it provides a good reason to return to this fascinating place with its mosaic of environments.