More than 1000 species on Tespelduyn estate
Bioblitz news flash
On Saturday morning, July 19, 2025, Peter Duivenvoorde addressed the owners of 8 colored vests on the terrace of Tespelduyn. The colored vests were worn by the volunteers of the KNNV Bollenstreek who are mapping the flora and fauna of Tespelduyn with their Bioblitz, which has been reported on before. Today the limit of 1000 species would be passed. And Peter had a keen sense of that. That Saturday became a day full of species diversity. The goal is 1,500 species. In this Bioblitz newsflitz, a look back at that Saturday.
Moth work
The inventory work had already started on night from Friday to Saturday. Paul had already set up his LED bucket Friday night at a spot west of the parking lot. An LED bucket is a bucket with an LED light that attracts moths and micro butterflies at night. Butterflies then hide in the dark spots in bucket and can be viewed the next morning. Paul managed to determine the presence of 12 new species on Tespelduyn using this technique. In addition, there were as many as 20 Birdcatcher dot moths in his bucket.
Life in the Rhodondendrons
Not only wild plants on Tespelduyn bring new life. Plantings also contribute considerably! For what to think of a Rhodondendron bud eater and the Rhodondendron cicada? According to Adrie van Dam, two species that are linked together. The bud eater is a fungus that has been known to growers since the 1980s. This fungus causes damage to the flower buds, which then dry up. The plant then blooms less. The Society of Mycology (mushroom connoisseurs) only discovered and named the species around 2016.
And this Rhodondendron bud-eater is again spread by the Rhodondendron cicada that made the crossing from England to mainland Europe about 35 years ago. This cicada is beautifully bright green colored with orange stripes and, according to Adrie, have a shape similar to the supersonic helmets of the time trialists in the Tour de France. By the way, the Rhodondendron itself was not yet registered as 1 of the 1000 species on Tespelduyn. After all, in principle, only wild plants and animals are registered with the Bioblitz. Organisms fortunately do not care about boundaries and agreements that we as humans make.
Hanging in the willows
Tespelduyn has a lot of water on the estate and therefore has many willows. Some galls were found on those willows on Saturday by Agate. North of hole 9 a Curly willow, also called Kronkel Willow or Chinese willow. Here Agate saw signs of a Willow Witch's broom. Witch brooms are growths of plant buds caused by the presence of mites. In this case, the Willow Broom Mite. In that same willow, there was also an infestation on the buds by a gall midge that led to growths that we again call galls. The gall midge is called the Willow bud gall midge. In another willow, a Shoot willow, on the forest edge south of hole 8 we found, we found the galls of a Shoot willow wart mite. And on the same leaf with the galls of this Schietwilgwratmijt we also found a willow tree. A bladder-like fusion of the leaf that is again caused by the Bladder gall wasp. Are you still following along? The volunteers are not stopping the search yet, so they will not be hanging up their work on the willows.
Umbrella trap
Michel and Sjaak had gone into the field Saturday morning with an umbrella. Not because of a chance of rain. But the umbrella can then be used as a trap. The umbrella is slid upside down under some low-hanging branches of trees or bushes. The branches are then shaken briefly: And all the insects present then fall into the umbrella and can be quickly and easily identified. There is not much time. Most insects run or fly away quickly in search of a new hiding place. A magnifying glass comes in handy because some insects are less than half an inch in size and for that reason cannot be named with the naked eye.
Among the species they saw were Mugwort aphid, Mugwort leafhopper, Marsh sicklebug, Southern green shieldbug, Herb spindlebug, Great skitterbug, Short-winged sawbug, Hawthorn spindlebug and Blackthorn mallow. The Southern green shieldbug resembles the "common" green shieldbug, but is rare and heat-loving. The exotic is native to Ethiopia and dies during winters with average temperatures below 5°C. The common green scale bug can withstand that.
Bugs from the pond of hole 9
Wim had put on his boots. Again: Not because of the chance of rain. But because he likes to stroll under water for snails and other small aquatic animals. In pond on hole 9 he found a Water Scorpion. The Netherlands actually has no native scorpions. But the Water Scorpion is not a scorpion either. It is a bug with two long prehensile arms near its head. This makes the bug look like a scorpion. The bug can bite hard and has a long, non-retractable breathing tube at the back for breathing under the water surface. Furthermore, Wim found a rod bug. This bug is very elongated in shape and resembles a walking branch. This species was also found in the pond on hole 9.
Other critters in the water
Maud stayed on dry land that Saturday morning, but still managed to name the Dwarf Croos. Dwarf duckweed is one of the five species of duckweed known in the Netherlands. Duckweed is also called water lentils. On Sunday, July 20, Maud would go with Marijke Wagner to look for Plankton in the different water environments at Tespelduyn. Such work requires a lot of knowledge and expertise and we are glad that Marijke also knows how to get this group of organism above the water for us.
Broad wasp orchid
The broad wasp orchid is an orchid that was present on Tespelduyn as early as June. There were three specimens in one spot. How nice then that Sarah discovered that 100 meters away there was also a specimen of this beautiful orchid.
Wildlife cameras and night recordings
Within the volunteer team Sarah, Cees, Sjaak a Jim have been active to make recordings possible with motion cameras that can also record in the evening hours. And recently this has established the presence of a Waterral in the pond on hole 8. Such work takes a lot of preparation time and Cees has already done some inspection work on Saturday morning to see what setups are possible to establish the presence of marten. So far it has turned out that this is not an easy task.