Ivo Raemakers

Enhancing the diversity of mass‐flowering crops (i.e., crop diversity) in agricultural landscapes is often proposed as a measure to favour pollinators and pollination, but it is uncertain whether crop diversity enhances pollinator richness on the wide landscape level. Here, we surveyed pollinator communities in semi‐natural habitats and mass‐flower...

Bumble bees (Bombus) are a group of eusocial bees with a strongly generalised feeding pattern, collecting pollen from many different botanical families. Though predominantly generalists, some bumble bee species seem to have restricted dietary choices. It is unclear whether restricted diets in bumble bees are inherent or a function of local conditio...

Despite their miniature brains, insects exhibit substantial variation in brain size. Although the functional significance of this variation is increasingly recognized, research on whether differences in insect brain sizes are mainly the result of constraints or selective pressures has hardly been performed. Here, we address this gap by combining pr...

1. Agricultural expansion and intensification have resulted in strong declines in farmland biodiversity across Europe. In many intensively farmed landscapes, linear landscape elements such as field boundaries, road verges and ditch banks are the main remaining green infrastructures providing refuge for biodiversity, and as such play a pivotal role...

The Strepsiptera fauna of the Netherlands is revised. Recent molecular work provided new insights in the taxonomy of the genus Stylops, raising the number of species in Europe from one to thirty. With this knowledge all available Strepsiptera material from the Netherlands is reexamined and additional DNA barcode sequences are generated and analyzed...

Current conservation instruments, which for most species rely heavily on protected areas, are insufficient to halt biodiversity loss. Conservation initiatives in the wider landscape surrounding protected areas are needed to achieve the impact required for reversing negative biodiversity trends. Focussing on intensively used north-western European l...

As a response to concerns for the conservation of pollinator diversity, mitigation measures are being initiated in the Netherlands by a wide variety of organizations and private individuals. Most of these efforts focus on the restoration of floral resources, by sowing wildflower mixtures and/or improving terrain management. Such initiatives are, ho...

Conserving and restoring semi-natural habitat, i.e. enhancing landscape complexity, is one of the main strategies to mitigate pollinator decline in agricultural landscapes. However, we still have limited understanding of how landscape complexity shapes pollinator communities in both crop and non-crop habitat, and whether pollinator responses to lan...

Location data of the specimens used for DNA barcoding.

Thick-headed flies of the genus Myopa Fabricius are a common sight in early spring in Europe. Several species can befound flying among Salix catkins together with their supposed Andrena Fabricius hosts (Hymenoptera: Apidae) (John Smit observations). Despite the fact that some of these Myopa species are very common, little is known about their actua...

The sustainability of agriculture can be improved by integrating management of ecosystem services, such as insect pollination, into farming practices. However, large‐scale adoption of ecosystem services‐based practices in agriculture is lacking, possibly because growers undervalue the benefits of ecosystem services compared to those of conventional...

De laatste tijd is er veel aandacht voor de achteruitgang van bijen. Er zijn inmiddels veel initiatieven om wilde bijen een handje te helpen, meestal door het inzaaien van bloemenmengsels. Maar profiteren wilde bijen hier wel van? Welke soorten hebben daar het meest baat bij? Bevordert dit ook de bestuiving van naastgelegen gewassen? En waar moet r...

Smit et al. ‒ Leopoldius carceatus nu ook in nederland. Blaaskopvliegen zijn kleine tot grote (3-20 mm), meestal slank gebouwde vliegen. Het merendeel is geelzwart gekleurd, maar er zijn ook grijze, zwarte en geheel roodbruine soorten. Alle Europese soorten parasiteren op volwassen bijen of wespen. De eitjes worden in het achterlijf van de gastheer...

Deze rapportage geeft inzicht in de wilde-bijenfauna van Noord-Brabant. Vragen die aan bod komen zijn: welke bijensoorten komen er voor, welke gaan er voor- en welke achteruit? Voor welke soorten heeft deze provincie een speciaal belang en welke kunnen er als ’prioritair’gelden? Welke biotopen (volgens het systeem van beheertypen) zijn belangrijk v...

THE DUTCH BEES (HYMENOPTERA: APIDAE S.L.) In the Netherlands, 358 species of bees have been recorded. The knowledge of their distribution and biology has greatly improved over recent years, thanks to hundreds of people who contributed their observations. This book attempts to present the accumulated knowledge on the Dutch bees in an attractive fash...

In densely populated areas, roadside verges often provide the last semi-natural habitats available. Their ecological value is often stressed by bio survey results. Yet insect summer surveys potentially misjudge the value of a biotope (roadside or otherwise) since the occurrences of species may only be seasonal, or even transient. To effectively asc...

SCRAPES AT BEMELEN, AN IMPORTANT LANDSCAPE ELEMENT FOR BEES IN NUTRIENT-POOR GRASSLAND SYSTEMS In 2010, a nesting site of the endangered bee species Halictus quadricintus was discovered in a 1.5 ha grassland near the village of Bemelen, which features some scrapes (micro-cliffs). This is currently the only known nesting site of this species in the...

Het verklaren van populatietrends is een belangrijk doel geweest van een breed scala aan ecologische studies. Dergelijke studies worden bemoeilijkt doordat bij zeldzame soorten een bepaalde eigenschap of gedrag zowel oorzaak als gevolg kan zijn van de achteruitgang van een soort. Wij omzeilden dit probleem door eigenschappen van soorten te vergelij...

Synthesis of recent observations of Stenoria analis (Schaum) (Coleoptera, Meloidae) in France and in neighboring regions. - We provide a synthesis of records from France and neighbouring regions concerning Stenoria analis (Schaum), a parasitic beetle of Colletes nests in western Europe. The data gathered indicate that this blister beetle has expand...

Momenteel worden voor de Nederlandse Natura 2000 gebieden beheerplannen opgesteld. Voor het formuleren van richtlijnen en maatregelen, alsmede om de ontwikkelingen rond de habitattypen en doelsoorten in de toekomst te kunnen evalueren, is het noodzakelijk om de uitgangssituatie ten aanzien van de habitattypen en doelsoorten goed te beschrijven. Ook...

Urbanisation and intensifi cation of agriculture has led to large scale destruction of natural and seminatural areas in Western Europe. Consequentially, the conservation of biodiversity in small landscape units has become a matter of increasing urgency. In this paper, we inventoried the arthropod diversity in roadside verges in the Netherlands and...

Understanding population declines has been the objective of a wide range of ecological studies. When species have become rare such studies are complicated because particular behavior or life history traits may be the cause but also the result of the decline of a species. We approached this problem by studying species' characteristics on specimens t...

Insects and spiders comprise more than two-thirds of the Earth's total species diversity. There is wide concern, however, that the global diversity of arthropods may be declining even more rapidly than the diversity of vertebrates and plants. For adequate conservation planning, ecologists need to understand the driving factors for arthropod communi...

Passaloecus-soorten zijn nogal onopvallende zwarte graafwespjes. Doorgaans nestelen ze in stengels of gaten in hout, waarbij ze bladluizen als voedsel voor hun larven verzamelen. In 2007 werd Passaloecus pictus voor het eerst in ons land waargenomen. Ze nestelt, in tegenstelling tot de verwante soorten, in de bodem. De Nederlandse ontdekking sluit...

De staafmier staat bekend als zeldzaam, maar dat hangt samen met haar verborgen levenswijze. In deze bijdrage word eerst enkele opmerkelijke vindplaatsen van de staafmier uit het stedelijk gebied beschreven. De beschreven vondsten duiden erop dat de staafmier goed kan voorkomen in niet-natuurlijke situaties en mogelijk algemener is in het zuiden va...

Megachile pilidens new for the Netherlands (Hymenoptera: Apoidea: Megachilidae) Megachile pilidens Alfken 1924 is reported for the first time from the Netherlands. We also mention some new records in adjacent parts in Germany and Belgium. In Europe M. pilidens has a south-eastern distribution but recently expands to the north. Its occurrence seems...

Geleedpotigen leven onder steeds moeilijker omstandigheden. De gebieden waar ze leven raken steeds verder versnipperd. Om die reden is het belangrijk om de overgebleven soorten beter te beschermen. Zo ontstond er ook hernieuwde belangstelling voor het leven van geleedpotigen in bermen. Bermen blijken een belangrijke ecologische waarde te hebben. Di...

Illustrations of the genitalia of Bombus sylvestris and B. norvegicus in recent Dutch bumblebee keys (van der Blom 1984, 1989, 1996) are exchanged. With an overview of bumblebee keys in the Netherlands and surrounded countries.

New records of Andrena nitidiuscula in the Netherlands (Hymenoptera: Apidae) In 2005 Andrena nitidiuscula was observed from late June till mid August in a garden and a few other sites near Maastricht (Limburg). These observations are the first since 1950 and refute the classification as extinct in the Netherlands in the red list of Dutch bees. The...

Abstract Grazing at low stocking rates has become a common management practice in nature restoration projects in the Netherlands. However, detailed knowledge of grazing impact is often poor, in particular for invertebrates. This study addressed the impact of extensive grazing on butterflies. Butterflies are critical indicators of habitat quality fo...

Six insect groups were sampled in 10 roadside plant communities. Insect species richness appeared to be fairly high in road verges and endangered species were frequently encountered. A good correspondence was found between plant community and the overall insect species composition of the sites. The correspondence for the individual insect groups wa...

Some interesting records on Dutch bees (Hymenoptera: Apidae) The publication of the preliminary atlas of Dutch bees (Peeters et al. 1999) has stimulated many specialists in their mapping activity. The author reports several interesting new distribution records on ten bee-species in 1999. The Dutch Colletus halophilus Verhoeff, 1943 were thought to...

Eoferreola rhombica, a pompilid new to the Dutch fauna, and its remarkable host, Eresus sandaliatus (Hymenoptera: Pompilidae; Araneae: Eresidae) In 1998 a female specimen of Eoferreola rhombica (Christ, 1791) was collected in a road-verge on the Veluwe. The nearest populations of this species are found in northern France and eastern Germany. It is...

Until recently Boreus hyemalis was considered to be a rare species in The Netherlands. It was only known from a few localities in The Netherlands in the provinces of Noord-Holland, Zuid- Holland, Utrecht, Gelderland and Drenthe. The last few years many new populations have been discovered. In this paper the first records for the provinces of Limbur...

Sphecodes majalis, a new bee species for the Netherlands (Hymenoptera: Apidae) A population of Sphecodes majalis was found on a limestone grassland near Maastricht (Limburg). On several occasions more than 10 female and several male specimen were observed. Sphecodes majalis is a parasite of Lasioglossum pallens, which was recorded for the first tim...