Functional response ofCurinus coeruleus (Col.: Coccinellidae) toHeteropsylla cubana (Hom.: Psyllidae) on artificial and natural substrates

Laboratory measurements of the functional response of adultCurinus coeruleus (Mulsant) to nymphs ofHeteropsylla cubana Crawford on filter paper and on leaves of different host plants showed a significant effect of these different substrates on nymph consumption at several different densities. Moreover, this effect may be explained by the influence of the substrate on the search rate of the predator. Host plants tested includedLeucaena leucocephala (Lam) de Witt,L. diversifolia (Schlecht.) Benth. andL. pallida Britton and Rose. Results obtained may be relevant to plant-protection research programs involving the integration of biological control with host-plant resistance.      

Development of an <Emphasis Type="Italic">Agrobacterium</Emphasis>-mediated transformation protocol for the tree-legume <Emphasis Type="Italic">Leucaena leucocephala</Emphasis> using immature zygotic embryos

The tree-legume Leucaena leucocephala (leucaena) is used as a perennial fodder because of its fast-growing foliage, which is high in protein content. The use of leucaena as a fodder is however restricted due to the presence of the toxin mimosine. Improvements in the nutritional contents as well as other agronomic traits of leucaena can be accomplished through genetic transformation. The objective of this research was to develop a transformation protocol for leucaena using phosphinothricin resistance as the plant selectable marker. Explants obtained from immature zygotic embryos infected with the Agrobacterium tumefaciens strain C58C1 containing the binary plasmid pCAMBIA3201 produced four putative transformed leucaena plants. Transformation was confirmed by PCR, RT-PCR, Southern blot, Western analyses, GUS-specific enzyme activity and herbicide leaf spraying assay. A transformation efficiency of 2% was established using this protocol.     

The role of seed reserves in arbuscular mycorrhizal formation and growth of Leucaena leucocephala (Lam.) de Wit. and Zea mays L.

We show here that seed reserves in Leucaena leucocephala (Lam.) de Wit. and Zea mays L. (maize) are important for mycorrhizal formation and seedling growth. Seed reserve removal reduced mycorrhizal formation markedly in Leucaena but not in maize, except at 15 and 45 days after seed reserve removal. Partial or total removal of seed reserves decreased plant growth and tissue nutrient concentrations in both hosts. Nodule number in Leucaena, which was related positively to plant biomass and mycorrhizal infection levels, was reduced when one or both cotyledons were severed. Leucaena seedlings without or with partial seed reserves had higher nutrient use efficiencies throughout seedling growth. But such an effect was observed only initially in maize. Seed reserve removal increased the specific absorption rates of nutrients in both hosts. Phosphorus absorption rate was significantly and positively related to root infection levels in both Leuceana and maize. Though the growth rates of plants without seed reserves were low initially, these plants had higher growth rates during later stages. We conclude that seed reserves are not only important for seedling growth, but also for mycorrhizal formation and nodulation. Received: 15 July 1999 / Accepted: 6 December 1999     

Factors affecting production of COS and CS2 in Leucaena and Mimosa species

Carbon disulfide (CS₂) and carbonyl sulfide (COS) are colorless, foul-smelling, volatile sulfur compounds with biocidal properties. Some plants produce CS₂ or COS or both. When used as an intercrop or forecrop, these plants may have agronomic potential in protecting other plants. Most of the factors which affect production of these plant-generated organic sulfides are unknown. We determined the effects of sulfate concentration, plant age, nitrogen fixation, drought stress, root injury (through cutting), and undisturbed growth on COS production in Leucaena retusa or Leucaena leucocephala and the effect of some of these factors on CS₂ production in Mimosa pudica. In addition, we determined if organic sulfides were produced in all Leucaena species. When L. retusa and M. pudica seedlings were grown in a plant nutrient medium with different sulfate concentrations (50 to 450 mg SL^-1), COS or CS₂ from crushed roots generally increased with increasing sulfate concentration. COS production was highest (74 ng mg^-1 dry root) for young L. retusa seedlings and declined to low amounts (<5 ng mg^-1 dry root) for older seedlings. Nitrogen fixation reduced the amounts of COS or CS₂ produced in L. leucocephala and M. pudica. Under conditions of undisturbed growth, root cutting, or drought stress, no COS production was detected in 4-to 8-weeks-old L. retusa plants. COS or CS₂ or both was obtained from crushed roots or shoots of all 13 known Leucaena species.     

Contrasting effects of an invasive ant on a native and an invasive plant

When invasive species establish in new environments, they may disrupt existing or create new interactions with resident species. Understanding of the functioning of invaded ecosystems will benefit from careful investigation of resulting species-level interactions. We manipulated ant visitation to compare how invasive ant mutualisms affect two common plants, one native and one invasive, on a sub-tropical Indian Ocean island. Technomyrmex albipes, an introduced species, was the most common and abundant ant visitor to the plants. T. albipes were attracted to extrafloral nectaries on the invasive tree (Leucaena leucocephala) and deterred the plant’s primary herbivore, the Leucaena psyllid (Heteropsylla cubana). Ant exclusion from L. leucocephala resulted in decreased plant growth and seed production by 22% and 35%, respectively. In contrast, on the native shrub (Scaevola taccada), T. albipes frequently tended sap-sucking hemipterans, and ant exclusion resulted in 30% and 23% increases in growth and fruit production, respectively. Stable isotope analysis confirmed the more predacious and herbivorous diets of T. albipes on the invasive and native plants, respectively. Thus the ants’ interactions protect the invasive plant from its main herbivore while also exacerbating the effects of herbivores on the native plant. Ultimately, the negative effects on the native plant and positive effects on the invasive plant may work in concert to facilitate invasion by the invasive plant. Our findings underscore the importance of investigating facilitative interactions in a community context and the multiple and diverse interactions shaping novel ecosystems.     

Are psyllids affiliated with the threatened plants Acacia ausfeldii,A. dangarensis and A. gordonii at risk of co‐extinction?

Secondary extinctions of dependent affiliate species may exceed the numbers of species directly extirpated with habitat loss. We investigated the host specificity, and hence the co‐extinction risk, of multiple psyllid species (Hemiptera: Psylloidea) on the threatened plants Acacia ausfeldii, A. dangarensis and A. gordonii by sampling from these and other sympatric common plants across multiple sites, years and plant phenologies. We found one specialist psyllid species (Psyllidae: Acizzia sp.) on each of the plants A. ausfeldii and A. gordonii but no specialists on A. dangarensis. The A. gordonii specialist only occurred when its host was in flower. Specialist psyllids considered at risk of extinction represented 10% of all psyllid species observed on the three threatened acacias. Potential risks to co‐endangered affiliates need to be considered when implementing threatened plant recovery actions. Conservation of plant populations and plant species diversity is also necessary to maintain high insect diversity.     

Biology and epidemics of Candidatus Liberibacter species,psyllid‐transmitted plant‐pathogenic bacteria

Candidatus Liberibacter species are Gram‐negative bacteria that live as phloem‐limited obligate parasites in plants, and are associated with several plant diseases. These bacteria are transmitted by insects called psyllids, or jumping plant lice, which feed on plant phloem sap. Citrus huanglongbing (yellow shoot) or citrus greening disease is associated with three different species of Ca. Liberibacter – Ca. L. asiaticus, Ca. L. africanus and Ca. L. americanus – all originally found on different continents. Ca. L. asiaticus is the most severe pathogen, spread by Asian citrus psyllid Diaphorina citri and causing devastating epidemics in several countries. Ca. L. africanus occurs in Africa where it is spread by the African citrus psyllid Trioza erytreae. Ca. Liberibacter solanacearum is associated with diseases in several solanaceous plants, and transmitted by potato psyllid Bactericera cockerelli. Zebra chip disease is causing large damage in potato crops in North America. In Europe Ca. Liberibacter solanacearum is associated with diseases of the Apiaceae family of plants, carrot and celery, and transmitted by psyllids Trioza apicalis and Bactericera trigonica. When Ca. Liberibacter is suspected as the disease agent, the diagnosis is confirmed by DNA‐based detection methods. Ca. Liberibacter‐associated plant diseases can be controlled by using healthy plant propagation material, eradicating symptomatic plants, and by controlling the psyllid populations spreading the disease.     

Transgenic overexpression of Leucaena β-carbonic anhydrases in tobacco does not affect carbon assimilation and overall biomass

The role of β-carbonic anhydrases (CAs) in C₃ plant carbon assimilation is not clear. In this study, the primary role of C₃ plant β-CAs in carbon assimilation was investigated for which, a chloroplastic β-CA gene (cacp) and a cytoplasmic β-CA gene (cacyt) from a C₃ tree-legume of tropics, Leucaena leucocephala (leucaena) were overexpressed in Nicotiana tabacum (tobacco). The cacp and cacyt β-CA isoforms from leucaena were overexpressed separately and also together in tobacco resulting in three types of transgenic tobacco plants (i) expressing cacp only (ii) expressing cacyt only and (iii) co-expressing both cacp and cacyt. These transgenic plants exhibited significantly higher activity of β-CAs as compared with wild-type plants. The percent increase in the CA activity of transgenic plants expressing leucaena cacyt or cacp was found to be ～51 and ～55%, respectively. The transgenic tobacco expressing both the leucaena β-CA isoforms exhibited ～63% increase in CA activity as compared with the wild-type. However, despite notable increase in the CA activity of transgenic tobacco plants, no difference was observed in their phenotype, chlorophyll content and the overall dry weight compared with that of wild-type suggesting that C₃ β-CAs are not involved in active accumulation of inorganic carbon.     

Reproductive performance of South African indigenous goats inoculated with DHP-degrading rumen bacteria and maintained on Leucaena leucocephala/grass mixture and natural pasture

This study examined the reproductive performance of dihydroxy pyridone (DHP)-inoculated South African indigenous (SAIG) female goats maintained on two dietary treatments: (i) Leucaena leucocephala/grass mixture and (ii) natural pasture prior to conception, and during gestation. Leucaena leucocephala/grass mixture was nutritionally superior (crude protein and mineral elements) than the natural pasture. The average daily gain, products of pregnancy and foetal development in gravid goats raised on leucaena/grass mixture were significantly (P<0.03, P<0.009 and P<0.005, respectively) higher than those raised on natural pasture. Conception rate of goats fed natural pasture was higher than the band fed Leucaena leucocephala/grass mixture. Leucaena/grass mixture fed goats had kids that were heavier at birth than their counterparts on natural pasture. Pre-weaning kid mortality over the period of study was significantly (P<0.01) higher in the Leucaena leucocephala/grass mixture treatment. Colostrum from kidded goats fed leucaena was viscous and difficult to sample. The absence of mimosine toxicity symptoms suggests a possibility of safe use of leucaena as a feed resource to DHP-inoculated SAIG.     

Experimental Infection of Plants with an Herbivore-Associated Bacterial Endosymbiont Influences Herbivore Host Selection Behavior

Although bacterial endosymbioses are common among phloeophagous herbivores, little is known regarding the effects of symbionts on herbivore host selection and population dynamics. We tested the hypothesis that plant selection and reproductive performance by a phloem-feeding herbivore (potato psyllid, Bactericera cockerelli) is mediated by infection of plants with a bacterial endosymbiont. We controlled for the effects of herbivory and endosymbiont infection by exposing potato plants (Solanum tuberosum) to psyllids infected with “Candidatus Liberibacter solanacearum” or to uninfected psyllids. We used these treatments as a basis to experimentally test plant volatile emissions, herbivore settling and oviposition preferences, and herbivore population growth. Three important findings emerged: (1) plant volatile profiles differed with respect to both herbivory and herbivory plus endosymbiont infection when compared to undamaged control plants; (2) herbivores initially settled on plants exposed to endosymbiont-infected psyllids but later defected and oviposited primarily on plants exposed only to uninfected psyllids; and (3) plant infection status had little effect on herbivore reproduction, though plant flowering was associated with a 39% reduction in herbivore density on average. Our experiments support the hypothesis that plant infection with endosymbionts alters plant volatile profiles, and infected plants initially recruited herbivores but later repelled them. Also, our findings suggest that the endosymbiont may not place negative selection pressure on its host herbivore in this system, but plant flowering phenology appears correlated with psyllid population performance.     

Factors Influencing Host Plant Choice and Larval Performance in Bactericera cockerelli

Among the many topics of interest to ecologists studying associations between phytophagous insects and their host plants are the influence of natal host plant on future oviposition decisions and the mechanisms of generalist versus specialist host selection behavior. In this study, we examined the oviposition preferences, behavior and larval development of the tomato/potato psyllid, Bactericera cockerelli. By rearing psyllids with two distinct geographically-linked haplotypes on different host plants, we were able to examine the role of natal host plant and potential local adaptation on host plant usage. Choice bioassays among three host species demonstrated that psyllids from California had clear preferences that were influenced by natal plant. We further found that patterns in choice bioassays corresponded to observed feeding and movement responses. No-choice bioassays demonstrated that there is little to no association between development and host-plant choice for oviposition, while also indicating that host choice varies between haplotypes. These findings support the concept that mothers do not always choose oviposition sites optimally and also add support for the controversial Hopkins'' host selection principle.     

Nodulation and growth ofLeucaena leucocephala (Lam.) de Wit as affected by inoculation and N fertilizer

Leonard jar, pot and field experiments examined the effects of inoculation and the influence of nitrogen fertilizer on nodulation, nitrogen fixation and growth ofLeucaena leucocephala (Lam.) de Wit at IITA, Ibadan, Nigeria. Leucaena responded to both inoculation and/or nitrogen application. Shoot growth and total N and P of inoculated plants were comparable to those of the highest N treatment, and the values were about 55% greater than those of uninoculated ones. Field data indicated that toal N yields of inoculated leucaena were increased by 50% with 40 or 80 kg ha^–1 of N fertilizer. However, N fertilizer depressed N fixation by 56% as was expected from nodule mass data. N-fixation was delayed for about 8 weeks in the plots without N. Application of small amounts of N starter (20 ppm) proved to be beneficial to satisfy the plant need during the early stage of leucaena growth. The rhizobial strains IRc 1045 and IRc 1050 were effective, competitive and survived well in the field one year after their establishment.     

Diurnal Patterns of Flight Activity and Effects of Light on Host Finding Behavior of the Asian Citrus Psyllid

The Asian citrus psyllid, Diaphorina citri (Hemiptera: Psyllidae), is an invasive pest of citrus in the United States. The psyllid feeds and reproduces primarily on new flush growth of citrus and other rutaceous plants. Because it vectors the bacterial causal agents of the deadly citrus greening disease, D. citri is potentially a pest of economic importance in all citrus growing areas where it occurs together with the disease. We investigated the diurnal patterns of its flight activity in the field and the effects of light on its host selection and egg laying behaviors. The numbers of adult psyllids caught on yellow sticky traps were 3 to 4-fold higher during daytime than nighttime. Daytime flight activity of D. citri adults also varied with time of the day with peak catches occurring at midday from 1200 to 1500 h. Illumination of the traps at night increased their attractiveness to adult psyllids by 5-fold. Similarly, light significantly increased plant colonization by adults and female egg deposition on potted plants in the laboratory. These results showed that the flight activity and host selection behavior of adult psyllids are regulated by light and circadian rhythms. Thus, adult psyllids utilize light as visual cues in their host-plant selection process.     

Effect of liming and phosphorus application on performance ofLeucaena leucocephala in acid soils

Pot experiments were conducted to assess the lime and phosphorus requirements ofLeucaena leucocephala (LAM.) De Wit grown on three acid soils (Ultisols) from southeastern Nigeria. Liming and phosphorus application significantly enhanced growth ofL. leucocephala. Ammakama soil showed best effect to phosphorus application, while acidity problems were more pronounced on Onne and Isienu soils. High lime rate (2000 ppm) reduced plant growth in Isienu soil probably due to nutrient imbalance. Potassium, manganese and zinc levels in the plants were reduced with increasing lime rates. On Onne and Isienu soils plant tops correlated better with total acidity and extractable Al⁺³ level than with soil pH-H₂O.     

Host shift capability of a specialist seed predator of an invasive plant: roles of competition, population genetics and plant chemistry

Acanthoscelides macrophthalmus is a seed predator that has become widely distributed along with its native host, Leucaena leucocephala (Mimosoideae), which is a neotropical leguminous tree and one of the most invasive plants worldwide. Previous studies revealed that A. macrophthalmus is able to host-shift to several mimosoid species. Here, we aim to test the host-shift potential to other mimosoid and non-mimosoid plants and possible roles of interspecific competition, genetic background, and plant chemistry in host-shift. First, we found that A. macrophthalmus predator completed development on two new hosts: pigeon pea Cajanus cajan and Cajanus scarabaeoides (Faboideae), by rearing from seeds collected in South/Southeast Asia and Hawaii. In contrast, in most regions, both Cajanus species were infested only by other beetle species. Second, we performed no-choice tests using 11 leguminous plants, covering all three subfamilies as potential hosts, including the two new hosts. A Taiwanese A. macrophthalmus population reared in the laboratory on Leucaena did not deposit eggs on any of the seeds of each tested species. To compare host-shift responses between populations, we also used a Hawaiian A. macrophthalmus population that had completed its development on freshly collected Leucaena seeds from the field. This population deposited eggs onto and hatching larvae burrowed into C. cajan seeds, although none developed beyond the larval stage. Third, the surface chemical composition of seed-pods of L. leucocephala and the two Cajanus species was dissimilar, although that of seeds was highly similar. Finally, all of the host-shifting A. macrophthalmus populations shared the same haplotypic group.     

RAPD characterisation of two neotropical hybrid legumes

An investigation of randomly amplified polymorphic DNA (RAPD) and polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) marker distribution was made for two well-characterised hybrids and their parents,Leucaena leucocephala andL. esculenta andParkinsonia aculeata andCercidium praecox. Three chloroplast DNA (cpDNA) markers identified the maternal parent of eachL. leucocephala ×L. esculenta hybrid. Fifteen species-diagnostic RAPD markers (invariant in one taxon and absent from the other) were always present in theLeucaena hybrid and assumed to be of nuclear origin, whilst three RAPD markers showed expression patterns identical to the cpDNA markers and were assumed to be of organellar origin. No RAPD or PCR-RFLP taxon-diagnostic markers were discovered for eitherP. aculeata orC. praecox. However, 21 RAPD markers were species-specific (polymorphic within one taxon but absent from the other) and Southern analysis indicated that none of the markers were of organellar origin. Only 67% additivity of markers specific toP. aculeata andC. praecox was demonstrated in the hybrids between these two species, whilst inLeucaena 97% additivity was demonstrated. Differences between the two hybridising situations were related to the behaviour of the molecular markers and the biology of the species.     

Response of Leucaena/Rhizobium symbiosis to mineral nutrients in Southwestern Nigeria

Pot and field experiments carried out at the International Institute of Tropical Agriculture (IITA) and at Fashola, Southwestern Nigeria, examined the effect of inoculation and N, P and micronutrients on nodulation and growth ofLeucaena leucocephala (Lam.) de Wit. In pot studies all parameters measured, except the percentage of nitrogen in shoots, were improved by inoculation, nitrogen and phosphorus. Micronutrients increased only nitrogen and allantoin contents. Interactions between inoculation and P, N and micronutrients on nodulation and growth of leucaena were observed. The effect of inoculation and fertilization with phosphorus or micronutrients was further investigated in field experiments. Establishment of uninoculated and unfertilized leucaena was poor at both locations due to low soil fertility and the presence of only a few native leucaena rhizobia. At one site, only inoculated plants were nodulated, while at the other, all plants produced nodules. Shoot dry weight, total nitrogen and phosphorus of inoculated plants were statistically equal to nitrogen-fertilized plants. Uninoculated plants were stunted. Generally, micronutrients did not influence nodulation, total nitrogen or growth of leucaena. They had only a positive effect on nitrogenase activity. Phosphorus increased total nitrogen and phosphorus uptake and plant growth. A 75% increase in shoot dry weight was obtained when 80 kg P ha^–1 was applied to inoculated leucaena with Rhizobium strain IRc 1045. Inoculated plants contained more allantoins than uninoculated ones but no significant correlation was found between these compounds and other parameters of N fixation.     

Effects of ectomycorrhizal and vesicular-arbuscular mycorrhizal fungi on drought tolerance of four leguminous woody seedlings

Seedlings ofAcacia auriculiformis A. Cunn. ex. Benth.,Albizia lebbeck (L.) Benth.,Gliricidia sepium (Jac.) Walp andLeucaena leucocephala (Lam.) de Wit. were inoculated with an ectomycorrhizal (Boletus suillus (l. ex. Fr.) or indigenous vesicular-arbuscular mycorrhizal (VAM) fungi in a low P soil. The plants were subjected to unstressed (well-watered) and drought-stressed (water-stressed) conditions. InGliricidia andLeucaena, both mycorrhizal inoculations stimulated greater plant growth, P and N uptake compared to their non-mycorrhizal (NM) plants under both watering regimes. However, inAcacia andAlbizia, these parameters were only stimulated by either ectomycorrhiza (Acacia) or VA mycorrhiza (Albizia). Growth reduction occurred as a result of inoculation with the other type of mycorrhiza. This was attributed to competition for carbon betweenAcacia and VA mycorrhizas and parasitic association betweenAlbizia and ectomycorrhiza. Drought-stressed mycorrhizal and NMLeucaena, and drought-stressed mycorrhizalAcacia tolerated lower xylem pressure potentials and larger water losses than the drought-stressed mycorrhizal and NMAlbizia andGliricidia. These latter plants avoided drought by maintaining higher xylem pressure potentials and leaf relative water content (RWC). All the four leguminous plants were mycorrhizal dependent. The higher the mycorrhizal dependency (MD), the lower the drought tolerance expressed in terms of drought response index (DRI). The DRI may be a useful determinant of MD, as they are inversely related.     

Short feeding period of carrot psyllid (Trioza apicalis) females at early growth stages of carrot reduces yield and causes leaf discolouration

Overwintered adult carrot psyllids [Trioza apicalis Förster (Homoptera: Psylloidea: Triozidae)] damage carrot [(Daucus carota ssp. sativum L.) (Apiaceae)] seedlings by phloem feeding on the leaves. The aim of this study was to investigate the carrot root and shoot growth in relation to carrot psyllid density during early growth stages. One, two, or three carrot psyllids were allowed to feed on carrot seedlings for 3 days. Leaf damage was measured at the 8‐leaf stage, and root, leaf fresh weight, and number of true leaves were measured at harvest. Both the age of the carrot seedling at infestation and the psyllid density had a significant effect on leaf damage at the 8‐leaf stage: seedlings damaged at the cotyledon stage exhibited more leaf damage than seedlings damaged at the 1‐leaf stage. A higher psyllid density significantly reduced the carrot root weight at harvest. The significant interaction of psyllid density with seedling age indicates that differently aged carrot seedlings responded differently to feeding: one psyllid feeding for 3 days at the cotyledon stage caused a significant yield loss, whereas three psyllids were needed to cause the same impact at the 1‐leaf stage. Carrot leaf weight at harvest was not reduced by carrot psyllid feeding: leaves recovered from the damage but roots did not. Our results confirm the farmers’ observations that a trap replacement period of 1 week for carrot psyllid monitoring is too long, especially at the cotyledon stage. Severe leaf discolouration on damaged carrots was observed at harvest. The possible reasons for this discolouration, such as toxin excreted in psyllid saliva or plant pathogenic mycoplasma infection, are discussed.     

Mycorrhizal and nonmycorrhizal host growth in response to changes in pH and P concentration in a manganiferous oxisol

Glomus aggregatum and Leucaena leucocephala were allowed to interact in a manganese-rich oxisol at pH 4.3–6.0 and at soil P concentrations considered optimal for mycorrhizal host growth and sufficient for nonmycorrhizal host growth. At 0.02 mg P l^-1, vesicular-arbuscular mycorrhizal fungal (VAMF) colonization of roots increased as soil pH increased from 4.3 to 5.0. However, VAMF colonization of roots did not respond to further increases in pH. At pH 6.0, growth of mycorrhizal Leucaena observed at 0.02 mg P was comparable with that observed at 0.8 mg P l^-1. Increasing P concentration from 0.02 to 0.8 mg P 1^-1 increased target soil pH from 4.3 to 4.7 and reduced the concentration of available soil Mn from 15.1 to 1.9 mg 1^-1. Thus, the normal plant growth observed at the higher P concentration at pH<5 was mainly due to the alleviation of Mn toxicity as a result of its precipitation by excess P. VAMF colonization levels observed at pH 5.0–6.0 were similar, but maximal plant growth occurred at pH 6.0, suggesting that the optimal pH for mycorrhizal formation was substantially lower than for VAMF effectiveness. The poor growth of Leucaena at the lower P concentration in the unlimed soil was largely due to high concentrations of Mn²⁺ and H⁺ ions.Contribution from the Hawaii Institute of Tropical Agriculture and Human Resources Journal Series No. 3910