Investigations into stability in the fig/ fig-wasp mutualism

Fig trees (Ficus, Moraceae) and their pollinating wasps (Chalcidoidea, Agaonidae) are involved in an obligate mutualism where each partner relies on the other in order to reproduce: the pollinating fig wasps are a fig tree’s only pollen disperser whilst the fig trees provide the wasps with places in which to lay their eggs. Mutualistic interactions are, however, ultimately genetically selfish and as such, are often rife with conflict. Fig trees are either monoecious, where wasps and seeds develop together within fig fruit (syconia), or dioecious, where wasps and seeds develop separately. In interactions between monoecious fig trees and their pollinating wasps, there are conflicts of interest over the relative allocation of fig flowers to wasp and seed development. Although fig trees reap the rewards associated with wasp and seed production (through pollen and seed dispersal respectively), pollinators only benefit directly from flowers that nurture the development of wasp larvae, and increase their fitness by attempting to oviposit in as many ovules as possible. If successful, this oviposition strategy would eventually destroy the mutualism; however, the interaction has lasted for over 60 million years suggesting that mechanisms must be in place to limit wasp oviposition. This thesis addresses a number of factors to elucidate how stability may be achieved in monoecious fig systems. Possible mechanisms include: 1) a parasitoidcentred short ovipositor hypothesis in Ficus rubiginosa, which suggests that a subset of flowers are out of reach to parasitoid ovipositors making these ovules the preferred choice for ovipositing pollinators and allowing seeds to develop in less preferred ovules; 2) the presence of third-party mutualists such as non-pollinating fig wasps (F. burkei) and patrolling green tree ants on the fig surface (F. racemosa) that limit pollinator and parasitoid oviposition respectively; and 3) selection on fig morphology which constrains the size (and therefore fecundity) of the associated pollinators. I discuss the lack of evidence for a single unifying theory for mutualism stability and suggest that a more likely scenario is the presence of separate, and perhaps multiple, stabilising strategies in different fig/ fig-wasp partnerships

First record of the non-pollinating fig wasp Odontofroggatia galili Wiebes, 1980 from Malta (Hymenoptera, Chalcidoidea, Agaonidae)

The fig wasp Odontofroggatia galili is reported for the first time from Malta. Odontofroggatia is a non-pollinating fig wasp genus associated with a narrow range of host plant species, among them Ficus microcarpa, a widespread ornamental tree native to Asia.peer-reviewe

In vitro and in vivo anthelmintic efficacy of plant cysteine proteinases against the rodent gastrointestinal nematode, Trichuris muris

We examined the mechanism of action and compared the anthelmintic efficacy of cysteine proteinases from papaya, pineapple, fig, kiwi fruit and Egyptian milkweed in vitro using the rodent gastrointestinal nematode Heligmosomoides polygyrus. Within a 2 h incubation period, all the cysteine proteinases, with the exception of the kiwi fruit extract, caused marked damage to the cuticle of H. polygyrus adult male and female worms, reflected in the loss of surface cuticular layers. Efficacy was comparable for both sexes of worms, was dependent on the presence of cysteine and was completely inhibited by the cysteine proteinase inhibitor, E-64. LD50 values indicated that the purified proteinases were more efficacious than the proteinases in the crude latex, with purified ficin, papain, chymopapain, Egyptian milkweed latex extract and pineapple fruit extract, containing fruit bromelain, having the most potent effect. The mechanism of action of these plant enzymes (i.e. an attack on the protective cuticle of the worm) suggests that resistance would be slow to develop in the field. The efficacy and mode of action make plant cysteine proteinases potential candidates for a novel class of anthelmintics urgently required for the treatment of humans and domestic livestock

Use of leaf thickness sensors in horticultural crops

Changes in leaf thickness can be a rapid indicator of the plant’s water status and can therefore serve as an alarm signal for potential water deficits. Combining the use of continuous leaf thickness measurements with a mechanistic plant model describing optimal leaf growth and diel variations, would allow growers to optimize greenhouse growing conditions by adaptation of the microclimate and applied irrigation. Recent development of new sensors offers the possibility for real time measurements of leaf thickness on small plants, including ornamentals. However, the accuracy of leaf thickness variation measurements needs to be assured. In this study, the temperature influence on 12 LeafSen (Netafim, Tel Aviv, Israel) sensors has been tested in a temperature range from 16 °C to 31 °C by installation of the sensors on aluminium plates. Temperature variations in the investigated range resulted in sensor signal differences of up to 48 μm, indicating that temperature response can exceed the expected diel leaf thickness variation. Two typical temperature responses were distinguished, pointing to the need for a sensor specific temperature correction. The practical use of leaf thickness sensors and the established temperature corrections has been demonstrated by installing the sensors on the stem and leaf of three Ficus plants (Ficus benjamina) and three pot roses (Rosa chinensis cv.) starting from cutting stage in a commercial greenhouse environment

A new species of Phyllophaga Harris from the island of Navassa in the Caribbean (Coleoptera: Scarabaeidae: Melolonthinae)

The small Caribbean island of Navassa (U.S. possession) is unoccupied by humans, but recent surveys have detected a surprising number of endemic (precinctive) invertebrates. A new species of May beetle, Phyllophaga navassa, is here described and compared to the Hispaniolan Phyllophaga fauna

On some arthropods associated with Ficus species (Moraceae) in the Maltese Islands

An account is given on the 39 arthropod species which were found on different Ficus trees in the Maltese Islands. Seventeen species represent new records for Malta including Anothopoda fici, Asetadiptacus emiliae, Astichus bachmaieri, Ecphylus caudatus, Empoasca alsiosa, Eupristina verticillata, Ficocyba ficaria, Gynaikothrips ficorum, Josephiella microcarpae, Philotrypesis caricae, Pleistodontes sp., Rhaphitelus maculats, Rhyncaphytoptus ficifoliae, Scobicia chevrieri, Silba adipata, Singhiella citrifolii and Zanchius breviceps. Anothopoda fici and Zanchius breviceps, also represent new records for the entire European territory. Of the 39 arthropods, 33 feed on Ficus trees, whereas the rest are either parasitoids or predators of some of these plant feeders. The 33 species which use Ficus as their host-plant spend most of their development on and utilise the aforementioned trees as their main source of food, at least during their larval development.peer-reviewe

A broad typology of dry rainforests on the western slopes of New South Wales

Dry rainforests are those communities that have floristic and structural affinities to mesic rainforests and occur in parts of eastern and northern Australia where rainfall is comparatively low and often highly seasonal. The dry rainforests of the western slopes of New South Wales are poorly-understood compared to other dry rainforests in Australia, due to a lack of regional scale studies. This paper attempts to redress this by deriving a broad floristic and structural typology for this vegetation type. Phytogeographical analysis followed full floristic surveys conducted on 400 m2 plots located within dry rainforest across the western slopes of NSW. Cluster analysis and ordination of 208 plots identified six floristic groups. Unlike in some other regional studies of dry rainforest these groups were readily assigned to Webb structural types, based on leaf size classes, leaf retention classes and canopy height. Five community types were described using both floristic and structural data: 1) Ficus rubiginosa–Notelaea microcarpa notophyll vine thicket, 2) Ficus rubiginosa–Alectryon subcinereus–Notelaea microcarpa notophyll vine forest, 3) Elaeodendron australe–Notelaea microcarpa–Geijera parviflora notophyll vine thicket, 4) Notelaea microcarpa– Geijera parviflora–Ehretia membranifolia semi-evergreen vine thicket, and 5) Cadellia pentastylis low microphyll vine forest. Floristic groupings were consistent with those described by previous quantitative studies which examined smaller portions of this study area. There was also general agreement between the present analytical study and a previous intuitive classification of dry rainforest vegetation throughout the study area, but little concurrence with a continental scale floristic classification of rainforest

Comparative Antioxidant Activity on the Ficus Benjamina and Annona Reticulata Leaves

Antioxidants can prevent free radical formation. Natural antioxidants found in many plants, such as Ficus benjamina and Annona reticulata. The study aimed to compare the antioxidant activity of extracts and fractions of Ficus benjamina and Annona reticulata leaves against 1,1-diphenyl-2-picrilhydrazyl. The steps of this study consist of extraction, fractionation with n-hexane, ethyl acetate and water, phytochemical screening, antioxidant activity determination, and comparing the IC50 values. Percentage scavenging activity of the extracts and fractions against DPPH was calculated to determine the antioxidant activity. The IC50 value of Ficus benjamina was 127.86 ppm for ethanolic extract, 94.01 ppm for water fraction, 115.48 ppm for ethyl acetate fraction, and 335.50 ppm for n-hexane fraction. The IC50 value of Annona reticulata was 274.31 ppm for ethanolic extract, 211.42 ppm for water fraction, 367.91 ppm for ethyl acetate fraction, and 741.08 ppm for n-hexane fraction. The results showed that the Ficus benjamina water fraction was the best antioxidant compared to other extract and fraction