Influence of the Foraging Activity of the Anthophilous Insects on Talinum triangulare (Waterleaf) fructification in Bafut (North West - Cameroon)

Talinum triangulare is an herbaceous succulent plant eaten as a vegetable throughout the tropics including many countries in West and Central Africa and are an essential ingredient in traditional dishes. Experiments were made on the plant to examine the influence of foraging behavior of flowering insect on pollination and yields of this plant species in 2018 and 2019 at Bafut. Observations were made on 1615 to 4055 flowers per treatment. The treatments included unlimited floral access by visitors and bagged flowers to deny all visits. The study focused on the foraging behavior of flowering insects and their pollination activity (fruiting rate). The results show that 14 insect species visited waterleaf flowers and Camponotus flavomarginatus was the most frequent (33.20%). Insects foraged throughout the day light period. Their activity was highest between 10 am and 12 pm. Insect species foraged the flowers for pollen and nectar. The fructification rate of unrestricted floral access was significantly high than that of protected flowers to deny all visits. The maintenance of insect nest close to T. triangulare field is recommended to improve it fruits production.

Honey bee contribution to canola pollination in Southern Brazil

Although canola, (Brassica napus L.), is considered a self-pollinating crop, researchers have indicated that crop productivity increases as a result of honey bee Apis mellifera L. pollination. Given this crop's growing importance in Rio Grande do Sul State, Brazil, this work evaluated the increase in pod and seed productivity with respect to interactions with anthophilous insects and manual pollination tests. The visiting frequency of A. mellifera was correlated with the crop's blooming progression, and productivity comparisons were made between plants visited by insects, manually pollinated plants (geitonogamy and xenogamy) and plants without pollination induction. Pod set and seed production per plant were determined for each treatment. Among the 8,624 recorded flower-visiting insects, Hymenoptera representatives were the most prevalent (92.3%), among which 99.8% were A. mellifera. The correlation between these bees and blooming progression was positive (r = 0.87; p = 0.002). Pollination induction increased seed productivity from 28.4% (autogamy) to 50.4% with insect visitations, as well as to 48.7 (geitonogamy) and to 55.1% (xenogamy) through manual pollination.

Mechanical vs. Beetle-mediated Self-pollination in Gossypium Tomentosum (Malvaceae), an Endangered Shrub

Experimental hand pollinations of the endangered, Hawaiian, endemic, Gossypium tomentosum Nutt. Ex. (Malvaceae) showed that it was self-compatible, but self-pollination resulted in reduced reproductive output. Field observations and pollen tube analyses using fluorescence microscopy showed that mechanical self-pollination in this species included a mechanism known as bending stigmas. A receptive stigma bent backwards and contacted dehiscent anthers in 7% of flowers found on 17 G. tomentosum plants. The yellow flowers were nectarless and were not visited by most anthophilous insects in situ except for the introduced, nitidulid beetle, Aethina concolor Macleay. Collections and insect GI-tract dissections showed that A. concolor carried and ate the pollen of the host flower. Field observations recorded regular contact between beetles and stigma lobes as these insects exited the flowers effecting self-pollination. Behavioral experiments showed that the beetles responded positively to a yellow visual cue. Under some circumstances, an introduced pollen vector may help maintain a low level of reproductive success in an insular endemic.

Fossil evidence for the evolution of biotic pollination

The Cretaceous-Paleogene history of plants and insects reveals a discernible pattern in the evolution of floral character complexes and insects. Earliest Cretaceous flowers were small apetalous magnoliids with few parts. They co-occurred with a greater variety of anthophilous insects than has previously been supposed, and the idea that Coleoptera were the principal early insect pollinators is in need of review. By the mid-Cretaceous rosid flowers are known with well-developed corollas and the Rosidae are diverse by the late Cretaceous. The more derived asterid floral types are not firmly established until the Tertiary. Nectaries are present in many of the late Cretaceous rosids and may signal the beginning of the most significant evolutionary interaction between H ym enoptera and angiosperms. Advanced floral types in M aastrichtian and early Tertiary deposits are consistent with the appearance of meliponine Apideae (Stingless honeybees) in the late Cretaceous.