Spatial variation in impacts of brushtail possums on two Loranthaceous mistletoe species

Browsing by introduced brushtail possums is linked to major declines in mistletoe abundance in New Zealand, yet in some areas mistletoes persist, apparently unaffected by the presence of possums. To determine the cause of this spatial variation in impact I investigated the abundance and condition (crown dieback and extent of possum browse) of two mistletoes (Alepis flavida, Peraxilla tetrapetala) and abundance and diet of possums in two mountain beech (Nothofagus solandri var. cliffortioides) forests in the central-eastern South Island of New Zealand. Mistletoe is common and there are long-established uncontrolled possum populations in both forests. Mistletoes were abundant (216?1359 per hectare) and important in possum diet (41?59% of total diet), but possum density was low (c. 2 per hectare) in both areas. Possum impacts were slight with low browse frequencies and intensities over much of the study sites. However, impacts were significantly greater at a forest margin, where possum abundance was highest, and at a high-altitude site where mistletoe density was lowest. Mistletoe crown dieback was inversely proportional to intensity of possum browsing. These results suggest that the persistence of abundant mistletoe populations at these sites is due to mistletoe productivity matching or exceeding consumption by possums in these forests of low possum-carrying capacity, rather than low possum preference for the local mistletoe populations.     

Long‐term response of temperate canopy trees to removal of browsing from an invasive arboreal herbivore in New Zealand

Defoliation of forest tree canopies by herbivores and other agents, leading to tree mortality and reduced productivity, threatens the ecological stability of forests globally. This study shows that long‐term control of a mammalian arboreal folivore (brushtail possums; Trichosurus vulpecula Phalangeridae) reduces crown dieback and increases foliage cover in browsing‐damaged canopy trees. We monitored indices of possum density, possum browsing, tree foliage cover and crown dieback for 20 years following initiation of possum control in 1994 that repeatedly reduced possum densities to near zero every 5–6 years and kept the population below 35% of pre‐control levels over the entire period. Observable possum browsing was recorded on 20–49% of individuals of three palatable tree species at the time of first control. Those percentages fell to zero after control and never exceeded 2–10% for individual species over the next 19 years. We recorded significant increases in foliage cover attributable to recovery from defoliation by possums for all three species during the first 10 years. Large increases in foliage cover occurred on individuals that were heavily browsed in 1994 (mean increases: 36–89%), but mean population increases were modest (3–19%) because only 10–19% of trees were initially heavily browsed. Twenty‐year mortality rates were similar for plants with, or without, initial possum browsing, indicating no residual impact of pre‐control browsing on tree mortality. Times for full recovery of crown foliage cover varied from 10 years for the youngest trees and faster growing species to more than 20 years for mature individuals of the slowest growing species.     

Heterogeneity in vertebrate and invertebrate herbivory and its consequences for New Zealand mistletoes

Vertebrate herbivores generally have greater effects than invertebrates on plants. However, few studies have investigated the effects of both invertebrate and vertebrate herbivores on a single plant species. In New Zealand, nationwide declines in mistletoe populations have often been attributed to possum herbivory, but never to insect herbivory. The main goal of the present study was to document levels of vertebrate and invertebrate herbivory on endemic New Zealand mistletoe plants to suggest whether herbivory is leading to mistletoe decline. In the present study, the annual amount of leaf loss from herbivory by the brushtail possum (Trichosurus vulpecula), insect herbivory and leaf abscission were measured in two populations each of three mistletoe species (Alepis flavida, Peraxilla colensoi, and Peraxilla tetrapetala, Loranthaceae). In two populations of each species from February 1997 to February 1998, abscission accounted for the most leaf loss (range 10–84% of total mean leaf area, mean 33%), whereas insects and possums usually removed small and similar amounts (less than 3%). Possum browse caused large amounts of abscission in only one population (A. flavida at Eglinton). Observed possum browse was more heterogeneous than insect browse among branches within a plant (possum coefficient of variation = 2.63, insect CV = 1.98, P < 0.001), among plants in a population (possum CV = 2.15, insect CV = 0.69, P < 0.001), and between populations (possum CV = 1.36, insect CV = 1.09). Moreover, insects damaged 100% of the study plants but never removed more than 16% of leaf area on a single plant, whereas possums only browsed 32% of the study plants but severely defoliated some plants. Thus, while the mean amount of biomass removed across a population may have important consequences for mistletoe survival, the effect of possums on mistletoe populations may also depend on the heterogeneity of browse among individuals in the population.     

Use of mistletoes by the Grey Go‐away‐bird (Corythaixoides concolor,Musophagidae) in a semi‐arid savannah,south‐west Zimbabwe

Mistletoes are preferred nesting sites for many bird species in a range of habitats. However, no studies have examined the use of mistletoes by nesting birds in the semi‐arid savannah. We studied nesting in mistletoe and its role in determining nesting success in the Grey Go‐away‐bird in south‐west Zimbabwe. We modelled the effects of mistletoe, mistletoe abundance, nest microclimate, concealment and nest height on daily survival rates (DSR) using program MARK. A constant survival model was best fitted for the Grey Go‐away‐bird suggesting a constant nest survival rate across the nesting period. Mistletoe nests had lower DSR than nests placed elsewhere in the canopy. Mistletoe abundance and nest height had a positive association with DSR whereas visibility distance, microclimate and concealment were negatively associated with DSR. Overall, survival for nests in mistletoe was 22.1% compared with 90.5% for nests in other substrates over the 50‐day nesting period. In conclusion, the low nest survival in mistletoe suggests either that the factors used to select mistletoe as nest sites by these birds are poor predictors of nest success or that nesting in mistletoe may be maladaptive.     

Ship rat demography and diet following possum control in a mixed podocarp–hardwood forest

Control of one pest species may permit increases in abundance of other pests, thereby reducing the overall net benefit from pest control. We provide evidence that control of introduced possums (Trichosurus vulpecula) may increase ship rat (Rattus rattus) abundance in some New Zealand native forests. Ship rat abundance in a podocarp–hardwood forest was assessed using simple interference indices over 14 years (1990–2004) that included two aerial possum-poisoning operations (1994, 2000). Ship rat demography and rat and possum diet were measured from June 2001 to June 2003 when the rat population was increasing after the 2000 poisoning. Mean ship rat abundance indices increased nearly fivefold after possum control and remained high for up to 6 years after the 1994 poisoning. Rat fecundity was high (50–100% of adult females breeding), even during winter, and young animals dominated the population (73% in age classes 1–3) in 2001–2002 when rat numbers were increasing. During 2002–2003, rat abundance stabilised, without marked winter or spring reductions, the population aged significantly (only 32% in age classes 1–3), and fecundity declined to low levels (4–27% of adult females breeding). Although seeds and fruit dominated the diet of rats driving population recovery after control (74.0% of total diet by dry weight), rat fecundity was instead closely correlated with the proportional consumption of invertebrates (r = 0.91). Juvenile survival was correlated with proportional seed consumption (r = 0.75), while adult survival was correlated with combined seed and invertebrate consumption (r = 0.83). Adult rats ate more seeds and fewer invertebrates than juvenile rats. Seeds and fruit also dominated possum diet (52.2% of total diet). These results are consistent with the hypothesis that increased rat abundance following possum control is a consequence of greater availability of, or reduced competition for, seeds and fruit.     

The effect of Gratiana boliviana (Coleoptera: Chrysomelidae) herbivory on growth and population density of tropical soda apple (Solanum viarum) in Florida

The effect of herbivory by Gratiana boliviana Spaeth (Coleoptera: Chrysomelidae) on the invasive, tropical soda apple (TSA) (Solanum viarum Dunal, Solanaceae), was investigated using exclusion methods and by monitoring the density of G. boliviana and the weed at four locations over a period of 40 months. TSA plants protected by insecticide were taller, wider, and had greater canopy cover that unprotected plants, and plants in closed cages were taller and wider than those in open cages. Survival of plants was higher in plots protected with insecticide than in unprotected plots in both years of a 2-year study. In the population dynamics study, the initial density of TSA was 4–5 times higher at one of the locations than at the other three sites, but within 3 years, TSA density at the high density site had declined by 90%. At the three sites which initially had a low abundance of TSA, density remained low throughout the study. The intrinsic rate of increase of G. boliviana varied between –3.9 and 4.5, but over the 3-year study, was not different from zero, indicating a stable population. The intrinsic rate of increase was lower than zero for the period from October to January, and greater than zero during the January to April period. In the periods from April to July and July to October, the rate of increase was not different from zero. The implications of these results for biological control of TSA in Florida are discussed.     

温室瓜蚜种群动态的研究

瓜蚜AphisgossypiiGlover在温室黄瓜上的空间格局为聚集分布,分布的基本成分为个体群,聚集强度随密度的上升而下降;瓜蚜主要分布于中部和下部叶片。瓜蚜在温室黄瓜上呈指数增长,模型为Nt=0.1745e0.7414t(r=0.9676)。应用最优分割法将瓜蚜种群动态划分为3个阶段:初建期、发展期和高峰期。在种群初建期,有翅蚜开始迁入,数量较低,以扩散为主,分布不均匀,聚集强度较高;在发展期,瓜蚜种群不断繁殖扩散,分布日趋均匀,聚集强度逐渐下降;在高峰期,瓜蚜种群数量急剧增长到最高峰,分布至所有植株,聚集强度继续下降,此阶段后由于黄瓜植株受害枯萎,瓜蚜缺少食物而数量急剧下降。     

The relationship between possum density and browse damage on kamahi in New Zealand forests

To minimize the impacts of introduced pests and to justify and prioritize pest control, managers need to know the relationship between pest density and damage. This relationship can be difficult to quantify because pest impacts can be highly variable. In New Zealand, introduced brushtail possums (Trichosurus vulpecula) browse a wide range of native forest species. However, possum browse is extremely patchy making it difficult to quantify the relationship between density and damage, meaning the benefits of reducing possum densities are poorly understood. We quantified patterns of possum browse on kamahi (Weinmannia racemosa), a common canopy tree species, at 21 forest sites that were repeat‐measured over an 8‐year period in the North Island, New Zealand, during which time possum densities fluctuated widely. We fitted a multilevel statistical model in order to quantify the relationship between possum density and browse damage while simultaneously quantifying how browse varied among trees, sites and years. Higher possum densities were associated with greater browse damage, but browse was also patchily distributed among trees at the same site, and among sites and years for a given possum density. This heterogeneity meant there was no simple density damage relationship, with the relationship differing from tree to tree and among sites and years. Our results show that at most sites reductions in possum density would have little benefit in reducing the probability of heavy browse on kamahi trees, but at a few sites there would be substantial benefits. This approach provides insights into the pattern and potential causes of variability in possum impacts, and a quantitative basis for prioritizing sites for possum control.     

Comparison of impact between carrot and cereal 1080 baits on tomtits (

This study investigates the hypothesis that tomtits are significantly less susceptible to 1080 poison operations when cereal rather than carrot bait applications are used, both at relatively low sowing rates. We made counts of territorial male tomtits along transects during standard 1080 possum control operations in 2001 to 2003. The transects had 3?5 kg ha-1 sowing rates of either carrot or cereal baits. The case-study evidence, all from operations that reduced possum populations to below five percent residual trap-catch, indicates that cereal bait operations with low sowing rates and large bait size have little, if any, immediate impact on tomtit populations. These results should be taken into account when planning aerial 1080 operations, especially given the contrasting evidence that carrot operations, even at low sowing rates, can have a negative impact on tomtits.     

Diet and impacts of brushtail possum populations across an invasion front in South Westland, New Zealand

Impact of the irruptive fluctuation in abundance of brushtail possum populations since their initial colonisation was investigated in the forests of South Westland, New Zealand. Possum abundance, fecundity, and diet, the condition of common possum-palatable tree species, and the abundance of common forest birds were measured at three sites occupied by possums for c. 10, 20, and 30 years. Possum densities were highest at the site where possums had been present for c. 20 years. Possum fecundity was higher at the site they had recently colonised than at the two sites where they had been present for c. 20–30 years. Diet of possums where they had recently colonised was dominated by highly preferred foods (72% of total diet), whereas these same foods contributed just 36% of total diet at the site where possums had been present for more than two decades. Canopy condition of common possum-preferred trees was scored progressively lower in areas with increasing length of possum occupation, especially at the site where the possum population had apparently declined from its maximum density. Native forest bird abundance also declined with increasing length of possum occupation. The implications of these results for management are discussed.     

Browse on mahoe and kamahi leaf-fall as a trigger for possum control

Introduced brushtail possums (Trichosurus vulpecula) are controlled over large parts of New Zealand to protect canopy trees. The condition of canopy trees is one of the cues used to trigger possum control, but selecting an indicator of canopy tree condition is difficult because many factors unrelated to possum browsing can affect canopy condition, and indices based on canopy scoring may not always quickly detect real changes in possum herbivory. We therefore investigated the usefulness of the percentage of fallen mahoe (Melicytus ramiflorus) and kamahi (Weinmannia racemosa) leaves browsed by possums (‘fallen-leaf browse’ or ‘FLB’) as a trigger for control aimed at protecting these tree species. We collected leaves falling from kamahi and mahoe trees every two months for two years at two study areas in the central North Island, one with initially high possum abundance (Oriuwaka) and the other with low possum abundance (Otupaka). We classified each of 92 384 leaves as either not-browsed, possum-browsed or insect-browsed. There was a strong and similar seasonal pattern in the mean number of fallen leaves per tree for both mahoe and kamahi at both study areas; fewest leaves fell in winter, and the most leaves fell in spring and early summer. Mahoe and kamahi FLB exhibited a similar seasonal pattern at both areas, being lowest in winter and highest in spring and early summer. FLB for both mahoe and kamahi declined following control of possums to low densities at Oriuwaka. The proportion of fallen mahoe and kamahi leaves browsed by possums was small compared with those browsed by insects or not browsed. We show that spring/early summer (i.e. September–December) is the best period for sampling FLB and that the mean FLB can be estimated with a CV of 20% if one trap is randomly placed under the canopy of each of 24 randomly located trees. However, CVs were much larger in other seasons and when possum abundance was low. We consider FLB to be a sensible trigger for initiating possum control when the objective of control is to protect canopy trees, but further work is needed to determine the relationships between possum abundance, FLB, canopy condition, and key tree demographic rates.     

The contribution of mistletoes to nutrient returns: Evidence for a critical role in nutrient cycling

Both nutrient cycling and nutrient relationships between mistletoe and host have been widely studied; yet it is unclear whether high nutrient concentrations commonly found in mistletoes affect rates of nutrient cycling. To address this question, we assessed 13 elements in the leaf litter of a temperate eucalypt forest in southern New South Wales, comparing concentrations from trees (Eucalyptus blakelyi, E. dwyeri, and E. dealbata) with and without the hemiparasitic mistletoe Amyema miquelii. Results were in accord with previous research on fresh leaves showing that concentrations of many elements were higher in the mistletoe than the host. This was not the case for all elements; most notably for N, where concentrations were significantly lower in the mistletoe. However, the return of all elements increased with mistletoe infection because of the combined effect of enrichment in mistletoe tissues and high rates of mistletoe litterfall. Annual returns of N and P in leaf litter increased by a factor of 1.65 and 3 respectively, with the greatest increase being for K by a factor of 43 in spring. These increased element returns were not significantly influenced by any changes in host leaf litter quality, as mistletoe infection was not found to affect host element concentrations. Mistletoe infection also altered the spatial and temporal distribution of element returns because of the patchy occurrence of mistletoes and extended period of mistletoe litterfall compared with the host. These findings provide a mechanistic explanation for the role of mistletoes as a keystone resource and, together with comparable results from root‐parasitic plants in boreal tundra and cool‐temperate grasslands, suggest that enhancing nutrient return rates may be a generalized property of parasitic plants.     

Factors influencing brushtail possum (

Damage by introduced brushtail possums (Trichosurus vulpecula) to Pinus radiata trees was assessed in 41 compartments of a commercial forestry plantation on the Coromandel Peninsula, New Zealand. All the trees assessed were less than 3 years old. Possum damage in the compartments was low (median prevalence 3.3%) but highly variable (range 0?30%). Eight of 37 measured habitat factors differed significantly (P < 0.05) between the sites with damaged and undamaged trees. The best predictor of mean damage was stand age, but this explained only 21% of the variation in damage among compartments. Including both stand age and New Zealand bracken (Pteridium esculentum) cover improved the model significantly and explained 36% of variation in damage. Damage was apparently unrelated to compartment size, distance from the compartment boundary, and possum den-site availability. Surprisingly, the relationship between browse damage and a trap-catch index of possum abundance was weakly negative (r_S = −0.53, P = 0.05). The dense understorey associated with young pine stands tends to increase possum damage to associated P. radiata trees, but the possums in such stands may be less mobile at ground level and thus less easily trapped. Assessment of stand age and understorey characteristics, together with visual inspection for early signs of damage, is likely to be more cost-effective than possum surveys for identifying forest compartments at risk from possum browse.     

AGE STRUCTURE OF PHORADENDRON JUNIPERINUM (VISCACEAE), A XYLEM-TAPPING MISTLETOE: INFERENCES FROM A NON-DESTRUCTIVE MORPHOLOGICAL INDEX OF AGE

We investigated the age-structure of the xylem-tapping mistletoe Phoradendron juniperinum in relation to characteristics of its host tree, Juniperus osteosperma. We first correlated branch structure in the mistletoe with age of the mistletoe infection as determined anatomically; this correlation provided a nondestructive, field method of obtaining age structure information. We then surveyed the mistletoe plants, applying our aging index, within a population of their host trees in southwestern Utah; the majority of mistletoe plants were 2–12 years old. This peak in abundance of mistletoe infections showed no correlation to total annual precipitation within or 1 year previous to the peaks, minimum winter temperature, or to warmer than average winter temperatures. However, there was a positive correlation (r = 0.51, P < 0.06) with the amount of summer precipitation. A log-linear analysis indicated that a greater than expected number of mistletoe infections occurred at 5–7 years of age and at approximately 3 m in height among all host trees. We suggest that this pattern resulted because this canopy position had greater leaf and branch areas and was visited most frequently by seed-dispersing birds. The log-linear analysis also revealed that fewer than expected mistletoe infections occurred at ages older than 10 years, yet our data indicate that plants can reach 20 years of age. The lack of infections > 10 years of age was correlated to a period of below average precipitation, especially during the growing season, but not with cold winter temperatures, which in other studies had been suggested as a factor influencing mortality. We feel that drought may play an important role in influencing mistletoe mortality through its direct affect on host tree water status, but in addition we offer two alternative hypotheses to explain mistletoe longevity; the first is concerned with the relationship between carbon and nitrogen costs and maintaining large leaf areas in older plants, and the second addresses how increased hydraulic resistance in older and larger plants may be too costly for the plant, and stems are abscised.     

Reproductive biology and responses to threats and protection measures of the total population of a Critically Endangered Galápagos plant,Linum cratericola (Linaceae)

We describe a reproductive and population dynamic study of the total population of a Critically Endangered plant over 10 years, during which part of the population was protected from the main threat, feral ungulates. Linum cratericola (Linaceae) was first discovered in 1966 at two sites on Floreana Island, Galápagos. It has since disappeared from one site and survives in three groups of plants at the other, where it has been threatened with extinction by introduced ungulates and invasive plants. Population size, and growth rate and mortality of individual plants, have been monitored since 1997. The population appears highly responsive to changes in threat levels: the three plant groups increased rapidly following protection by fencing and ungulate control, but temporarily declined when feral goat pressure increased and during dry periods. Natural factors that may contribute to population limitation include dry years, grazing by native snails and competition from native vascular plants and cryptogams. Linum cratericola has a single flowering period per year and produces abundant seed with 28% germination after scarification, but with no obvious adaptations for long‐distance dispersal. Potential pollinators included the butterfly Leptotes parrhasioides, the hoverfly Toxomerus crockeri and the carpenter bee Xylocopa darwinii, all endemic to Galápagos. The continued survival of L. cratericola in the wild depends on effective protection from introduced herbivores and invasive plants. © 2009 The Linnean Society of London, Botanical Journal of the Linnean Society, 2009, 161 , 89–102.     

Host-preference and density of woodrose-forming mistletoes (Loranthaceae) on savanna vegetation,South Africa

In the Bushbuckridge region of South Africa host preference and density of two woodrose-forming mistletoes, Erianthemum dregei (Eckl. & Zeyh.) V. Tieghem and Pedistylis galpinii (Schinz ex Sprague) was quantified in relation to land-use (harvested or unharvested), rainfall (high > 660 or low < 660 mm year^–1) and catenal position (top or lower slope). These two mistletoes are generalist hemi-parasites of savanna trees and shrubs occurring on 25 and 17 hosts respectively, seven of which are shared. Thirty-six percent of woody plant species recorded were found to be hosts. Although Sclerocarya birrea (A. Rich.) Hochst. comprised only 4% of woody plant density in the environment, it was the principal host for both mistletoes, accounting for 71% of total E. dregei and 42% of P. galpinii infection. Mistletoe infection relative to density of Ficus stuhlmanii, Trichilia emetica and Cassine transvaalensis indicated that these were preferential hosts to S. birrea. Mistletoe host preference was negatively correlated with host wood density. Mistletoe number per tree had a weak relationship to canopy size. Mistletoes of all size classes were denser at high rainfall relative to low rainfall sites. Interestingly, the overall mistletoe size class distribution was similar between harvested and unharvested sites. The ratio of living to dead mistletoe was 2 to 1 for E. dregei and 1.5 to 1 for P. galpinii. There are sufficient dead mistletoes in unharvested and harvested areas to satisfy present market demand. Living E. dregei predominated in harvested rather than unharvested areas suggesting that current-harvesting levels had little or no negative effect on the population. In contrast, P. galpinii was denser in unharvested areas possibly owing to its higher market value and thus higher harvesting levels.     

槲寄生蛋白抗癌活性研究及新成分鉴定

目的评价槲寄生蛋白的抗癌活性,鉴定其中的新成分。方法以H22肝癌移植瘤为模型,评价槲寄生蛋白对肿瘤生长的抑制作用。采用CMSepharoseF．F．弱阳离子交换色谱,分离出一种低含量的槲寄生蛋白。基质辅助激光解吸飞行时间质谱测定其分子量。蛋白电泳后转印PVDF膜,采用Edman降解,测定该成分A,B两链的N端序列。结果槲寄生蛋白对H22的抑制率达80．2％,其中的CMO为未见报道的新成分。结论槲寄生总蛋白主要含有3种成分,且具有显著的抗癌活性。     

The impact of brodifacoum on non-target wildlife: gaps in knowledge

To assess the effect of possum browse on plant growth, an index of the amount of foliage on about 50 trees of Fuchsia excorticata and the number of trees that died or were completely defoliated was measured at five sites in South Westland over 5 years. This index was compared to possum density indices taken at each site each year. At one site, possums were reduced from a high density about 6 months before the final measurement. The degree of defoliation of fuchsia was significantly related to the density of possums at each site. Possums defoliate and kill fuchsia within two years once the catch-rate index of their density exceeds about 25%. However, this impact can be halted and quickly reversed by reducing possum density.     

Uncorrelated mistletoe infection patterns and mating success with local host specialization in <Emphasis Type="Italic">Psittacanthus calyculatus</Emphasis> (Loranthaceae)

Mistletoe infection between conspecific and interspecific hosts can be restricted by seed dispersal, host-mistletoe compatibility and abiotic factors, yet no studies have linked mistletoe infection patterns and pollination together for understanding mistletoe distribution at a local scale. Psittacanthus calyculatus (Loranthaceae) is a hemiparasitic plant with a broad host range across its geographic distribution. The potential for local host adaptation has been shown using cross-inoculation experiments, in which plants of mistletoe seeds collected from a given host are more likely to survive when they are inoculated on conspecific host trees compared with those inoculated on other host provenances. Here we evaluate host adaptation by describing the local patterns of infection (prevalence and intensity) of P. calyculatus mistletoes on three native host tree species (Alnus acuminata, Quercus crassipes, Salix bonplandiana) and one introduced species (Populus alba) and carried out cross-pollination experiments to examine how pollination affects infection patterns of different host species. Mistletoe infection prevalence (proportion of infection) and infection intensity (mean number of mistletoes per tree) were in general disproportional with respect to the availability of native host tree species but higher to that of non-native host tree species. Cross-pollination experiments showed higher mating success on the native host tree species, suggesting higher local adaptation to specially Q. crassipes. The observed spatial distribution of host tree species and mistletoe infection along with the non-random mating could contribute to local genetic structuring of mistletoe populations.     

Mistletoe species richness patterns are influenced more by host geographic range than nitrogen content

Mistletoes are hemiparasites that access water and nutrients from their hosts. Previous studies have suggested that host genera with high nitrogen are parasitized by more mistletoe species but these studies failed to take into account phylogenetic relationships among host genera. Our main question was whether more mistletoe species parasitize host genera with high nitrogen content when phylogenetic relationships were controlled. We also asked whether patterns in mistletoe parasitism were related to host geographic range size, host fruit type and host spinescence. Overall, we found no difference between conventional and phylogenetically controlled analyses. We also found no evidence for higher mistletoe species richness on host genera with high nitrogen, fleshy fruits or spinescence. However, similar to findings for animal parasites, we found that host genera with large geographic range had higher mistletoe species richness. This is likely because a greater number of mistletoe species will encounter hosts that have a greater geographic distribution. Mistletoe studies frequently assume that nitrogen status drives patterns in mistletoe parasitism but our study suggests that macroecological patterns in mistletoe assemblages are primarily determined by host geographic range.