Effects of Ozone and Sulfur Dioxide on Phyllosphere Fungi from Three Tree Species

Short-term effects of ozone (O₃) on phyllosphere fungi were studied by examining fungal populations from leaves of giant sequoia (Sequoiadendron giganteum (Lindl.) Buchholz) and California black oak (Quercus kelloggii Newb.). Chronic effects of both O₃ and sulfur dioxide (SO₂) were studied by isolating fungi from leaves of mature Valencia orange (Citrus sinensis L.) trees. In this chronic-exposure experiment, mature orange trees were fumigated in open-top chambers at the University of California, Riverside, for 4 years with filtered air, ambient air plus filtered air (1:1), ambient air, or filtered air plus SO₂ at 9.3 parts per hundred million. Populations of Alternaria alternata (Fr.) Keissler and Cladosporium cladosporioides (Fres.) de Vries, two of the four most common fungi isolated from orange leaves, were significantly reduced by chronic exposure to ambient air. In the short-term experiments, seedlings of giant sequoia or California black oak were fumigated in open-top chambers in Sequoia National Park for 9 to 11 weeks with filtered air, ambient air, or ambient air plus O₃. These short-term fumigations did not significantly affect the numbers of phyllosphere fungi. Exposure of Valencia orange trees to SO₂ at 9.3 parts per hundred million for 4 years reduced the number of phyllosphere fungi isolated by 75% compared with the number from the filtered-air treatment and reduced the Simpson diversity index value from 3.3 to 2.5. A significant chamber effect was evident since leaves of giant sequoia and California black oak located outside of chambers had more phyllosphere fungi than did seedlings within chambers. Results suggest that chronic exposure to ambient ozone or SO₂ in polluted areas can affect phyllosphere fungal communities, while short-term exposures may not significantly disturb phyllosphere fungi.     

Differential induction of chitinase in Piper colubrinum in response to inoculation with Phytophthora capsici,the cause of foot rot in black pepper

Plant chitinases have been of particular interest since they are known to be induced upon pathogen invasion. Inoculation of Piper colubrinum leaves with the foot rot fungus, Phytophthora capsici leads to increase in chitinase activity. A marked increase in chitinase activity in the inoculated leaves was observed, with the maximum activity after 60 h of inoculation and gradually decreased thereafter. Older leaves showed more chitinase activity than young leaves. The level of chitinase in black pepper (Piper nigrum L.) upon inoculation was found to be substantially high when compared to P. colubrinum. RT–PCR using chitinase specific primers revealed differential accumulation of mRNA in P. colubrinum leaves inoculated with P. capsici. However, hyphal extension assays revealed no obvious differences in the ability of the protein extracts to inhibit growth of P. capsici in vitro.     

Impact of the invasive tree black locust on soil properties of Mediterranean stone pine-holm oak forests

Background and aims

Invasion by N₂-fixing species may alter biogeochemical processes. We hypothesized that the grade of invasion by the N₂-fixer black locust (Robinia pseudoacacia L.) could be related to the distribution and pools of carbon (C) and nitrogen (N) along the profile of two Mediterranean mixed forests of stone pine (Pinus pinea L.) and holm oak (Quercus ilex L.).

Methods

A low-invaded (LIN) and a high-invaded (HIN) mixed forest were studied. We assessed: N concentration in green and in senescent leaves; C and N pools along the soil profile; seasonal changes of soluble C and N fractions, and microbial activity.

Results

Compared to coexisting holm oak and stone pine, black locust had higher N content in green and in senescent leaves. In the mineral soil: N stocks were similar in LIN and HIN; water soluble C and microbial activity, were lower in HIN compared to LIN; water soluble N showed seasonal changes consistent with tree growth activity in both HIN and LIN. In the organic layer of HIN, C and N stocks were about twofold larger than expected on the basis of stand density.

Conclusion

Black locust increased C and N stocks in the upper organic layers that are more vulnerable to disturbance. However, it did not increase N stocks in the mineral soil.     

Protein synthesis by 80S ribosomes during plant development

Protein synthesis by ribosomes from the meristematic region of pea roots (0–0·3 cm) and 2-day-old corn shoots (young tissues) relative to ribosomes from matured regions of pea roots (2·0–2·5 cm) and 10-day-old corn leaves (aged tissues) was compared in the poly U-phenylalanine system. With normal polyribosome preparations, ribosomes from young tissues required approx. 16 mM Mg²⁺ while ribosomes from aged tissues required 20–22 mM Mg²⁺ for optimal activity. With monomeric ribosome preparations induced by anaerobic treatment of the seedlings, the Mg²⁺ optimum was 20–22 mM for ribosomes from both young and aged tissues. A higher level of peptidyl-tRNA in ribosomes from young tissues accounts, at least in part, for the differences in Mg²⁺ optima between ribosomes from young and aged tissues. Monomeric ribosomes were used for assaying the activity of ribosomes per se. Ribosomes from young pea root tips and ribosomes from 2-day-old corn shoots were 25–30% and 100–150% more active, respectively, than the corresponding ribosomes from aged tissues. Differences in ribosomal proteins revealed by gel electrophoresis correlated with the change in ribosomal activity. Reduced activity in the aged ribosomes was not due to RNase activity or inhibitors.     

ent-Kaurene Biosynthesis in Cell-Free Extracts of Excised Parts of Tall and Dwarf Pea Seedlings

Investigations on the sites of ent-kaur-16-ene (ent-kaurene) biosynthesis were conducted with cell-free extracts from several excised parts of 10-, 13-, and 16-d-old tall and dwarf pea (Pisum sativum L.) seedlings. [¹⁴C]Mevalonic acid was incorporated into ent-kaurene in cell-free extracts from young developing leaves and elongating internodes of tall (`Alaska') and dwarf (`Progress No.9') pea seedlings at all three stages of development. ent-Kaurene biosynthesis also occurred readily in cell-free extracts from shoot tips, petioles, and stipules near the young elongating internodes. The ent-kaurene-synthesizing activity found in young developing tissues declined as tissues matured. Little or no activity was detectable in enzyme extracts from cotyledons and root tips at different stages. In light grown tall pea internodes ent-kaurene-synthesizing activity was low as they began to elongate, reached a maximum when the internodes reached about 2 cm in length and declined as they matured. Activity in extracts of dwarf shoot tips and internodes was generally lower than in equivalent tall plants, but the activity in dwarf leaves and stipules was somewhat higher than in tall plants. With the exception of root tips, there is a strong correlation between growth potential of a tissue and the rate of ent-kaurene biosynthesis in extracts from that tissue.     

Microbial Decomposition of Elm and Oak Leaves in a Karst Aquifer

Dry Chinquapin oak (Quercus macrocarpa) and American elm (Ulmus americana) leaves were placed in four microcosms fed by groundwater springs to monitor changes in dry mass, ash-free dry mass, and microbial activity over a 35-day period. Oxygen microelectrodes were used to measure microbial activity and to estimate millimeter-scale heterogeneity in that activity. Oak leaves lost mass more slowly than elm leaves. Generally, there was a decrease in total dry weight over the first 14 days, after which total dry weight began to increase. However, there were consistent decreases in ash-free dry mass over the entire incubation period, suggesting that the material remaining after initial leaf decomposition trapped inorganic particles. Microbial activity was higher on elm leaves than on oak leaves, with peak activity occurring at 6 and 27 days, respectively. The level of oxygen saturation on the bottom surface of an elm leaf ranged between 0 and 75% within a 30-mm² area. This spatial heterogeneity in O₂ saturation disappeared when the water velocity increased from 0 to 6 cm s^-1. Our results suggest that as leaves enter the groundwater, they decompose and provide substrate for microorganisms. The rate of decomposition depends on leaf type, small-scale variations in microbial activity, water velocity, and the length of submersion time. During the initial stages of decomposition, anoxic microzones are formed that could potentially be important to the biogeochemistry of the otherwise oxic aquifer.     

Physiological factors affecting the rapid decrease in protein assimilation efficiency by a caterpillar on newly‐mature tree leaves

Lymantria dispar L. caterpillars have a decreased ability to assimilate protein from mature leaves of red oak (Quercus rubra) compared with young, expanding leaves. The present study determines whether the drop in protein assimilation efficiency (PAE) occurs during the rapid phase of leaf maturation. Several mechanisms that might account for decreased PAE are also examined: mature leaf tissues could resist being chewed efficiently, protein in mature leaf tissues could become difficult to extract, and other nutrients in mature leaves might become growth limiting. The entire seasonal decrease in PAE occurs rapidly (in less than 2 weeks), when the leaves finished expanding. The maturation process is characterized by increased levels of fibre and decreased levels of water but no significant changes in the levels of protein or carbohydrates. Despite increased fibre in mature leaves, they are not chewed into larger food particles than are immature leaves. Carbohydrate assimilation efficiencies remain high on mature leaves, and signs of limiting water levels in larvae of L. dispar on mature leaves are not observed. The most important finding in the present study is the decreased extractability of protein in food particles from mature leaves, which plays a major role in explaining the rapid decrease in PAE. It is hypothesized that structural changes in cell walls during the rapid process of leaf maturation decrease protein extractability, which, in turn, greatly decreases the nutritional quality of mature oak leaves for caterpillars. The results of the present study therefore suggest a general mechanism to help explain the widely documented decrease in the nutritional quality of the mature leaves of many tree species for herbivorous insects.     

Fungal Growth, Production, and Sporulation during Leaf Decomposition in Two Streams

I examined the activity of fungi associated with yellow poplar (Liriodendron tulipifera) and white oak (Quercus alba) leaves in two streams that differed in pH and alkalinity (a hardwater stream [pH 8.0] and a softwater stream [pH 6.7]) and contained low concentrations of dissolved nitrogen (<35 μg liter⁻¹) and phosphorus (<3 μg liter⁻¹). The leaves of each species decomposed faster in the hardwater stream (decomposition rates, 0.010 and 0.007 day⁻¹ for yellow poplar and oak, respectively) than in the softwater stream (decomposition rates, 0.005 and 0.004 day⁻¹ for yellow poplar and oak, respectively). However, within each stream, the rates of decomposition of the leaves of the two species were not significantly different. During the decomposition of leaves, the fungal biomasses determined from ergosterol concentrations, the production rates determined from rates of incorporation of [¹⁴C]acetate into ergosterol, and the sporulation rates associated with leaves were dynamic, typically increasing to maxima and then declining. The maximum rates of fungal production and sporulation associated with yellow poplar leaves were greater than the corresponding rates associated with white oak leaves in the hardwater stream but not in the softwater stream. The maximum rates of fungal production associated with the leaves of the two species were higher in the hardwater stream (5.8 mg g⁻¹ day⁻¹ on yellow poplar leaves and 3.1 mg g⁻¹ day⁻¹ on oak leaves) than in the softwater stream (1.6 mg g⁻¹ day⁻¹ on yellow poplar leaves and 0.9 mg g⁻¹ day⁻¹ on oak leaves), suggesting that effects of water chemistry other than the N and P concentrations, such as pH or alkalinity, may be important in regulating fungal activity in streams. In contrast, the amount of fungal biomass (as determined from ergosterol concentrations) on yellow poplar leaves was greater in the softwater stream (12.8% of detrital mass) than in the hardwater stream (9.6% of detrital mass). This appeared to be due to the decreased amount of fungal biomass that was converted to conidia and released from the leaf detritus in the softwater stream.     

Intracellular Distribution of p-Nitrophenyl-Phosphatase in Plants

Less than 10% of the acid p-nitrophenylphosphatase activity of plant extracts was sedimentable under a variety of conditions including zonal centrifugation. The sedimentable fraction did not show the latency properties characteristic of animal lysosomes. We conclude that, at least operationally, plant acid phosphatase is a soluble enzyme and that it is not suitable as a lysosomal marker. The plant tissues employed were pea cotyledons, cauliflower florets, turnip storage organs, onion embryos, and leaves of red oak and soybean.     

Changes in UDPG: Sterol glucosyltransferase activity in Calendula officinalis

UDPG: sterol glucosyltransferase and acyltransferase which catalyse acylation of steryl glucosides are active in leaves, roots and flowers during the whole vegetative period of Calendula officinalis. The high activity of glucosyltransferase in young, developing tissues and its subsequent rapid decrease in activity in mature organs suggests that steryl glucosides are involved in the formation of some cell structures rather than in sterol transport as such within the plant.     

Spatiotemporal dynamics and plant-part preference patterns of the plant-visiting ants and the insect herbivores of sponge gourd plants

Field investigations revealed a synchrony between daily and seasonal activity patterns of two Raphidopalpa pests on the extrafloral nectary (EFN)-bearing sponge gourd, Luffa cylindrica (L.) plants. A similar pattern was revealed in six of the most abundant plant-visiting ant species. The spatial activity patterns of the herbivores R. foveicollis and R. intermedia revealed a high frequency on the leaves (except, newly unfolded leaves) and the corolla, but not on the bracts, bracteoles and the calyces of male/female buds and flowers. Young expanding leaves (leaf age class 2) had a significantly higher density of extrafloral nectaries (EFNs), as well as minimum leaf damage compared with the other leaf age classes. The density of EFNs was highest on the bracteoles and lowest on the leaves. In behavioural assays, ants demonstrated significantly greater preference for the 2-day old buds/newly opened leaves than the 2-day old intact unisexual flowers/corolla. Also, young, newly expanding leaves were preferred over young (unopened) and mature leaves. Thus, the higher density of EFNs at vulnerable plant sites, along with the visits of ants to such sites, may influence the spatiotemporal activity patterns of the insect herbivores. These results provide support for the optimal defense hypothesis since they show that younger tissues and reproductive tissues may be getting better protection by the ant species.     

Diurnal and seasonal changes of leaf lamina hydraulic conductance in bur oak (Quercus macrocarpa) and trembling aspen (Populus tremuloides)

The aim of this study was to examine the diurnal and seasonal variations in the sensitivity of leaf lamina (K _lam) hydraulic conductance to irradiance in bur oak (Quercus macrocarpa Michx.) and trembling aspen (Populus tremuloides Michx.), which vary in their responses of K _lam to irradiance. K _lam was determined using the high-pressure method and the measurements were carried out in June, August and September. The irradiance response of K _lam in bur oak was present throughout the day and declined in senescing leaves. In trembling aspen, K _lam declined from morning to late afternoon and drastically decreased before the onset of leaf senescence, but it was not sensitive to irradiance. In both tree species, the capacity of the petioles to supply water to leaf lamina changed during the day in accordance with the ability of the leaf lamina to transport water. Petiole hydraulic conductivity (K _pet) declined during the season in bur oak leaves, while it tended to increase in trembling aspen leaves. There was no correlation between the K _lam values and air temperature or light intensity at the time of leaf collection. For trembling aspen, K _pet was negatively correlated with the air temperature suggesting sensitivity to drought. We conclude that the water transport properties of petioles and leaf lamina in the two studied tree species reflect their ecological adaptations. Trembling aspen leaves have high hydraulic conductivity and high stomatal conductance regardless of the irradiance level, consistent with the rapid growth and high demand for water. In contrast, the increased lamina hydraulic conductivity and stomatal conductance under high irradiance in bur oak trees reflect a water conservation strategy.     

Radiative properties of hardwood leaves to ultraviolet irradiation

Spectral reflectance and transmittance of leaves to ultraviolet irradiation were determined under laboratory conditions for seven species of hardwood trees, namely red oak (Quercus rubra, L), black oak (Q. velutina, Lamarch), white oak (Q. alba, L.), sugar maple (Acer saccharum), Norway maple (A. plantanoides), hickory (Carya tomemtosa), sweetgum (Liquidambar styraciflua), and black oak litter. The experimental system consisted of a solar simulator, an integrating sphere, and a spectroradiometer. Experiments were repeated three to five times for both adaxial and abaxial surfaces of fresh leaves chosen at randomly. The spectral distributions and simple averages of the radiative properties in the wavelength ranges of ultraviolet-B (UV-B, 280–320 nm) and ultraviolet-A (UV-A, 320–400 nm) were determined. The spectral distributions of reflectance were similar between adaxial and abaxial surfaces, although the magnitude varied among tree species. Leaf reflectance was very low for the ultraviolet spectrum in general and varied among species and between adaxial and abaxial surfaces. It was generally higher over the UV-A waveband compared to UV-B, and higher on the abaxial than adaxial surface. The broadband reflectance in the UV-A range (over all species) was 5.0 and 3.9% for abaxial and adaxial surface, respectively, compared to 3.5 and 2.8% in UV-B. The transmittance through leaves was extremely small in the UV-B (<0.1%) and nearly zero in the UV-A spectral range. Consequently, the absorptance of ultraviolet radiation by leaves, as determined from the measured reflectance and transmittance, was quite high, being more than 90% for all the combinations of species and wavebands examined. The reported results are useful for studies requiring spectral radiative properties of the examined leaves with respect to ultraviolet irradiation.     

ACROPETAL LEAF DIFFERENTIATION IN QUERCUS RUBRA (FAGACEAE)

Northern red oak (Quercus rubra L.) leaves were shown to mature progressively from base to tip of the lamina based on studies of growth rates, anatomical differentiation, and ¹⁴C-transport. Lamina expansion in both length and width ceased in the basal quarter of the leaf before the apical quarter. Cell expansion and tissue differentiation were more advanced at the base than at the tip of leaves at 10%–20% of full expansion. Physiological data supported the morphological and anatomical data. Sink activity was examined by following the distribution of ¹⁴C imported into sink leaves with direct vascular connections to the source leaf to assure uniform assimilate supply to the sink leaves. Leaves approximately 50% of full expansion imported five to seven times more ^l4C-assimilates into the tip than into the base of the leaf, consistent with continued sink activity in the leaf tip after import by the leaf base has ceased. Transport of ¹⁴C from portions of the leaf, indicating source activity, occurred first in the basal portion of the lamina. The base functioned as a source at approximately 40% of full expansion; the tip, at approximately 60%. Thus, northern red oak displays an acropetal pattern of leaf expansion and differentiation, unlike the more typical pattern of basipetal leaf development defined in many other dicotyledonous genera with simple leaves.     

Fungal Endophytic Communities in Healthy and Declining Quercus robur L. and Q. cerris L. Trees in Northern Italy

Healthy and declining English oak (Quercus robur) and Turkey oak (Q. cerris) in north‐western Italy, in a plain oak forest showing decline for oak puzzle disease, were tested to assess possible variations in the composition of their fungal endophytic communities and their relation to the health status of trees. Samples collected in spring (buds) and in autumn (leaves, annual shoots and twigs) were surface‐sterilized, cut into fragments and placed on potato dextrose agar for a month; 26 fungal species were isolated, the most frequent being Tubakia dryina, Dendrodochium sp., Eutypella sp. and a sterile mycelium. Correspondence analysis showed significant qualitative differences between assemblages inhabiting twigs and herbaceous tissues that were due to the low frequency of Tubakia dryina in twigs and its higher frequency in buds, leaves and shoots. Tubakia dryina was isolated more frequently from leaves of declining oaks and from buds of healthy oaks; Monochaetia monochaeta showed a preference for healthy trees, especially leaves and buds. According to the Shannon–Wiener index, endophytic fungal communities of leaves, twigs and buds of declining English oak were poorer than those of declining Turkey oak, but there were no significant differences between healthy hosts.     

Importance of protein quality versus quantity in alternative host plants for a leaf-feeding insect

The nutritional value of alternative host plants for leaf-feeding insects such as caterpillars is commonly measured in terms of protein quantity. However, nutritional value might also depend on the quality of the foliar protein [i.e., the composition of essential amino acids (EAAs)]. A lack of comparative work on the EAA compositions of herbivores and their host plants has hampered the testing of this hypothesis. We tested the “protein quality hypothesis” using the tree-feeding caterpillars of Lymantria dispar (gypsy moth) and two taxonomically unrelated host plants, red oak (Quercus rubra) and sugar maple (Acer saccharum). Because L. dispar has higher fitness on oak than on maple, support for the hypothesis would be found if protein were of higher quality from oak than from maple. The whole-body EAA composition of L. dispar larvae was measured to estimate its optimum dietary protein composition, which was compared with the EAA compositions of oak and maple leaves. Contrary to the protein quality hypothesis, the EAA compositions of oak and maple were not significantly different in the spring. The growth-limiting EAAs in both tree species were histidine and methionine. Similar results were observed in the summer, with the exception that the histidine composition of oak was between 10 and 15 % greater than in maple leaves. The two main factors that affected the nutritional value of protein from the tree species were the quantities of EAAs, which were consistently higher in oak, and the efficiency of EAA utilization, which decreased from 80 % in May to <50 % in August. We conclude that the relative nutritional value of red oak and sugar maple for L. dispar is more strongly affected by protein quantity than quality. Surveys of many wild herbaceous species also suggest that leaf-feeding insects would be unlikely to specialize on plants based on protein quality.     

Natural and constrainment-induced factors influencing the breakdown of dogwood and oak leaves

Breakdown rates and microbial colonization patterns of dogwood and oak leaves were measured between November and June of 1987–88 and 1988–89. Leaves were placed in artificial streams loose (unconstrained), in bags, or in packs. Discharge was maintained at approximately 0.25 s^–1, and no shredders were present in the streams. Average microbial biomass as ATP, for all species and treatments, increased from near 0 mg g^–1 AFDW in November to over 8 mg g^–1 AFDW in June. Microbial respiration increased from about 0.01 µg glucose respired hr-g^–1 AFDW in November to about 0.03 µg hr-g^–1 AFDW in June. Microbial biomass and activity were significantly greater on dogwood leaves than on oak leaves. Dogwood and oak leaf breakdown rates were fastest when unconstrained, –0.0034 and –0.0027 degree-day^–1 respectively. Breakdown rates of dogwood leaves were faster in bags (–0.0025 degree-day^–1) than in packs (–0.0015 degree-day^–1) while rates of oak leaves were not significantly different between bags and packs (–0.0014 and –0.0018 degree-day^–1 respectively). Breakdown rates of dogwood and oak leaves obtained in this study were much slower than those obtained by other investigators either in the presence or absence of shredders. A comparison of results from this study with results from other studies revealed that dogwood leaves may be affected more by turbulence, while oak leaves may be influenced more by shredder activity.     

Functional response and reproductive attributes of the aphidophagous ladybird beetle,Harmonia dimidiata (Fabricius) in oak trees of sericultural importance

Harmonia dimidiata (Fabricius) (Coleoptera: Coccinellidae) is the dominant predator of the aphid species Cervaphis quercus Takahashi. This aphid is a serious pest of oak trees in several parts of north-east India. Young leaves of oak trees are used in sericulture by rural people and by industry in several parts of north-east India. The effect of different aphid densities on food consumption and fecundity of H. dimidiata was studied in the laboratory. Female beetles were maintained from the time of eclosion till death at a fixed density of 25, 50, 75,100 or 125 aphids. Both the functional response and the reproductive numerical response showed the upper asymptote at 100 adult aphids/female. At this density, females matured earlier and produced more eggs over a longer reproductive period. At lower prey densities, females matured late and they either did not produce eggs or produced fewer eggs. At the higher prey densities, females did not produce more eggs than the asymptote. Results suggested that H. dimidiata are an effective predator of C. quercus aphids on oak trees and could be exploited as a biological control agent in the rising phase of aphid population growth.     

Relationships of Histones to RNA Synthesis in Plant Tissues

The RNA-synthesizing activity of the tissue, template activity of the chromatin, histones and other parameters were analyzed for young leaves, senescent leaves and the pith tissue of tobacco. The amount, of RNA, DNA and the extent of incorporation of ³²P into RNA was much lower in old leaves and the pith tissue than in young leaves. Furthermore, the ³²P sucrose density gradient patterns of RNA from the three tissues were very different. In old leaves, the label was found mostly in low molecular weight RNA region, presumably as a result of degradation of RNA by soluble and chromatin-associated ribonucleases which were higher in old leaves. — In addition to significant differences in the composition of chromatin, large differences in the ratios of F_I : F_II : F_III : : histone fractions from the three tissues were noted and the fully differentiated old leaves and the pith tissue had proportionately more F_IIand F_III histones than the less differentiated young leaves. The F_III histone of tobacco differed from that of pea and calf thymus in having lys/arg = 1.2. — Although some correlation between RNA-synthesizing activity of the tissue, template activity of chromatin and the histone composition was noted for the pith tissue and the young leaves, the situation with old leaves was more complicated, probably due to the occurrence of chromatin-associated deoxyribonuclease and involvement of other factors which may also effect RNA synthesis.     

Fire triggers the activity of extrafloral nectaries,but ants fail to protect the plant against herbivores in a neotropical savanna

Herbivores are attracted to young shoots and leaves because of their tender tissues. However, in extrafloral nectaried plants, young leaves also attract patrolling ants, which may chase or prey on herbivores. We examined this scenario in extrafloral nectaried shrubs of Banisteriopsis malifolia resprouting after fire, which promoted both the aseasonal production of leaves and the activity of extrafloral nectaries (EFNs). Results were compared between resprouting (burned) and unburned control plants. The aggressive ant species Camponotus crassus and the herbivorous thrips Pseudophilothrips obscuricornis were respectively rapidly attracted to resprouting plants because of the active EFNs and their less sclerophyllous leaves. The abundance of these insects was almost negligible in the control (unburned) shrubs. Ants failed to protect B. malifolia, as no thrips were preyed upon or injured by ants in resprouting plants. Consequently, on average, 37 % of leaves from resprouting shrubs had necrosis marks. Upon contact with ants, thrips released small liquid droplets from their abdomen, which rapidly displaced ants from the surroundings. This study shows that P. obscuricornis disrupted the facultative mutualism between C. crassus and B. malifolia, since ants received extrafloral nectar from plants, but were unable to deter herbivore thrips.