What Is A Jack Jumper Ant: Learn About Australian Jack Jumper Ant Control


By: Mary H. Dyer, Credentialed Garden Writer

Jack jumper ants may have a humorous name, but there’s nothing funny about these aggressive jumping ants. In fact, jack jumper ant stings can be extremely painful, and some cases, downright dangerous. Read on to learn more.

Jack Jumper Ant Facts

What is a jack jumper ant? Jack jumper ants belong to a genus of jumping ants found in Australia. They are large ants, measuring about one-half inch (4 cm.), although the queens are even longer. When they’re threatened, jack jumper ants can jump 3 to 4 inches (7.5-10 cm.).

Natural habitat for jack jumper ants is open forests and woodlands, although they can sometimes be found in more open habitats such as pastures and, unfortunately, lawns and gardens. They are rarely seen in urban areas.

Jack Jumper Ant Stings

While jack jumper ants stings can be very painful, they don’t cause any real problems for most people, who experience only redness and swelling. However, according to a fact sheet distributed by the Tasmania’s Department of Water, Parks and Environment, the venom can cause anaphylactic shock in approximately 3 percent of the population, which is believed to be approximately double the rate for an allergy to bee stings.

For these people, jack jumper ant stings can lead to symptoms such as difficulty breathing, swelling of the tongue, abdominal pain, coughing, loss of consciousness, low blood pressure, and increased heart rate. The bites are potentially life threatening but, fortunately, deaths due to stings are very rare.

Severity of a reaction to jack jumper ant stings is unpredictable and may depend on a number of factors, including time of year, the amount of venom that enters the system or location of the bite.

Controlling Jack Jumper Ants

Jack jumper ant control requires use of registered pesticide powders, as no other methods are effective. Use pesticides only as recommended by the manufacturer. Nests, which are difficult to find, are usually located in sandy or gravelly soil.

If you’re traveling or gardening in Australia’s remote locations and you’re stung by a jack jumper ant, watch for signs of anaphylactic shock. If necessary, seek medical help as soon as possible.

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Tenterfield Pest Control

Ants are insects that have successfully colonized most places on the planet, except the Antarctic. It has been estimated that they make up as much as 15 to 20% of the biomass of all terrestrial animals.

Ants live in colonies and are social insects, with a hierarchy and caste system. The colonies can range from small to enormous, with millions of individuals. The caste system is the same as many social insects, with a queen at the top and different members of the colony fulfilling other functions.

Workers clean and maintain the nest as well as forage for food and look after the young. Soldiers protect the nest. Their defense mechanisms vary by species, some bite while others sting.

At certain times of the year winged ants appear, both males and females, which fly from the nest to start colonies elsewhere. The winged male ant is called a drone. After mating, the drone dies. The female sheds her wings and lays eggs, looking after the first generation which will become the workers.

Workers can travel relatively long distances in search of food, marking their paths with pheromones. When a good food source has been discovered, other ants will follow the pheromone trail to and from the nest. This is why ants are normally seen moving in columns.

Ant Problems

Ants can be a nuisance in any home. A piece of candy left on a table will soon have a trail of ants leading to it. Although ants discard wood debris and sawdust as they clean their nests, they do not damage sound timber. Any damage to wood is almost certainly due to termites not ants.

In parts of Australia, ants have become more than a nuisance. After being discovered in Cairns in 2001, the Yellow Crazy ant has spread rapidly northwards, causing mayhem where ever it appears. In Edmonton, one resident says he has been awoken three times at night by acid from the ants hurting his eyes. In some areas, residents have given up tending their gardens as they themselves get covered in the ants.

These same ants have adversely affected the Robber crab population in the Christmas Islands and as a consequence altered the type of plants that grow in that area. There is a fear that a similar effect could soon be seen in the Queensland wildlife. Agriculture in the region is being damaged to the tune of millions of dollars each year, an amount which is expected to grow dramatically unless the ants can be controlled. One report suggested that the cost could eventually be as high as A$3 billion.

The sting of the Jack Jumper ant (Myrmecia pilosula) can be fatal to sensitive people and an anti-venom is now available. Four deaths due to anaphylaxis caused by Jack Jumper ant stings were reported from Tasmania between 1980 and 2000. It is classed as one of the most dangerous ants in the world.

Species

Although there are over 1,300 known species of ant in Australia, only a few are pests. Pest species include the following:

  • Argentine ants (Linepithema humile) – a small species between 1.5 and 3mm long, light brown in color.
  • Coastal Brown ants (Pheidole megacephala) – light brown in color, between 1.5 to 2.5mm long.
  • Pharoah ants (Monomorium pharaonis) – variable in color from yellowish brown to darker brown. 1.5 to 2mm long.
  • Odorous ants (Tapinoma sessile) – another small species between 2 and 3mm, which like its name suggests gives off a rancid smell if crushed.
  • Carpenter ants (Camponotus species) – a larger species from 7 to 12mm in length and variable in color.
  • Meat ants (Iridomyrmex purpureus) – an even larger red and black species up to 15mm long.
  • Bull Dog ants (Myrmecia species) – an aggressive ant which can be 20mm long, red or black in color and has long jaws. These are primarily garden pests that can sting repeatedly.
  • Jack Jumper ants (Myrmecia pilosula) – a close relative of the Bull Dog ant, these 14mm long ants are black with orange jaws and legs. They are also known as Skipper ants or Hopper ants. They are a dangerous ant, responsible for deaths every few years due to anaphylactic shock caused by their sting.
  • Fire ants (Solenopsis species) – a small species, about 6mm long, that will normally build a mound in the garden but may invade a home. If disturbed they sting aggressively.
  • Yellow Crazy ants (Anoplolepis gracilipes) – only about 5mm long but listed in the top 100 worst invasive species of any plant or animal in the world. These ants don’t sting, but they may spray formic acid.

Control

The first step in controlling ants is to find their nest, which is not always easy. Spraying individuals or even lines of ants will not harm the colony, where thousands of others are available to take their place.

It is important to identify the species to be eradicated. Single queen colonies are easier to destroy than those with more than one queen. Incomplete extermination of a colony with more than one queen might cause the survivors to abandon the original site and split into several colonies.

In the garden or yard, colonies may build small mounds or nest next to or under boulders. Outdoors, their nests are invariably underground, so follow the lines of ants. Even if the entrance to the nest is small, soldier ants can normally be seen on guard outside. If a nest is found in the soil, it can be treated with various types of insecticide, such as a Pyrethoid or Bifenthrin liquid. The insecticides are pumped into the nest area, often under pressure.

Indoors, ants may build their nest in walls, under foundations or between bricks. Baits are normally used against an indoor ant invasion, placed in containers to avoid risk to children and pets. Like termites, ants are trophallaxic so the workers will take the insecticide bait back to the nest and share it among the other ants, leading to the death of the colony.

The bait will normally kill the ants within about three days. It should be placed near to or on the ant runs.


Best Overall: Terro T300B Liquid Ant Bait Ant Killer

When you want a no-fail way to get rid of pesky household ants, reviewers say TERRO T300 Liquid Ant Baits are their go-to solution. Made with Borax and other ingredients, they are pre-filled and easy to use: You simply cut the top off each bait with a pair of scissors and place it in a spot where you’ve seen a lot of ants. The baits come in packs of six, and should be kept away from pets or small children.

It’s important to note that while ant baits are generally very effective, they need time to interfere with an ant’s digestive system users may even initially see more ants before enough of the bait makes its way back to the colony. The manufacturer says the process can take up to two weeks, and it’s important to make sure they have nothing else to feast on, too. The vast majority of reviewers say these baits drastically reduced or eliminated their ant problem, and they love that there’s no smell or mess to deal with. Some do say that their ants ignored the bait, however, while a few others say the baits kept attracting ants but never actually stopped the onslaught.

"After setting these ant baits out in our kitchen and bathroom, we noticed an almost immediate uptick in ant activity. Don’t worry—that’s what’s supposed to happen. We saw the most visitors in the first few days, and then a steady stream continued for over a week, eventually trickling down in number until no ants were visible by two weeks."—Sarah Vanbuskirk, Product Tester


Professional Ant Control Process

Home remedies for ant infestations often do not address the root cause of the problem. If you want your house truly free of annoying ants, get help from the experts in ant pest control in Perth.

They make sure that every crack and crevice receives treatment, and they seek out those colonies and make sure they are completely destroyed. The process takes a few hours to one day at most. That way, no more black ants and such will bother your home.

Professional ant pest control in Perth will also advise you in preventing future infestation. Book an appointment with us today.

It’s important to identify the type of ants to give effective ant pest control in Perth and stop an ant infestation from wreaking further havoc. Different ants are identified according to their preferred food, nesting grounds and behaviour.


Results/Discussion

Sequencing, Assembly, and Annotation of the Atta cephalotes Genome

Three males from a mature Atta cephalotes colony in Gamboa, Panama were collected and sequenced using 454-based pyrosequencing [25] with both fragment and paired-end sequencing approaches. A total of 12 whole-genome shotgun fragment runs were performed using the 454 FLX Titanium platform in addition to two sequencing runs of an 8 kbp insert paired-end library, and one run of a 20 kbp insert paired-end library. Assembly of these data resulted in a genome sequence of 290 Mbp, similar to the 300 Mbp genome size previously estimated for A. cephalotes [30]. The genome is spread across 42,754 contigs with an average length of 6,788 bp and an N50 of 14,240 bp (Table 1). Paired-end sequencing (8 kbp and 20 kbp inserts) generated 2,835 scaffolds covering 317 Mbp with an N50 scaffold size of 5,154,504 bp. The disparity between contig and scaffold size may be accounted for by the number of repeats present in this genome (see below) leading to an inflated assembly size due to chimeric contigs. Based on the total amount of base pairs generated and its predicted genome size, we estimate that the coverage of the A. cephalotes genome is 18-20X.

To determine the completeness of the A. cephalotes genome sequence, we performed three analyses. First, we compared the A. cephalotes genome annotation against a set of core eukaryotic genes using CEGMA [31], and found that 234 out of 248 core proteins (94%) were present and complete, while 243 (98%) were present and partially represented. Second, we analyzed the cytoplasmic ribosomal proteins (CRPs) in the A. cephalotes genome and identified a total of 89 genes (Text S1). These encode the full complement of 79 CRPs known to exist in animals, nine of which are represented by gene duplicates (RpL11, RpL14, RpS2, RpS3, RpS7, RpS13, RpS19, RpS28) or triplicates (RpL22). The presence of a complete set of these numerous genes, which are widely distributed throughout the genome, confirmed the high-quality of the A. cephalotes genome sequence (Text S2). Finally, we found that the genome of A. cephalotes contains 66 of the 67 known oxidative phosphorylation (OXPHOS) nuclear genes in insects (Text S3). The only OXPHOS gene missing, cox7a, we found to also be missing in the two ants Camponotus floridanus and Harpegnathos saltator and the honey bee Apis mellifera. The presence of this gene in the jewel wasp Nasonia vitripennis (along with other holometabolous insects), suggests an aculeate Hymenoptera-specific loss, rather than a lack of genome coverage for A. cephalotes.

We also generated an annotation for the A. cephalotes genome using a combined approach of electronically-generated annotations followed by manual review and curation of a subset of gene models. Expressed Sequence Tags (ESTs) generated from a pool of workers consisting of different ages and castes from a laboratory-maintained colony of A. cephalotes was used in conjunction with the MAKER [32] automated annotation pipeline to generate an initial genome annotation. This electronically-generated annotation set (OGS1.1) contained a total of 18,153 gene models encoding 18,177 transcripts (See Materials and Methods), 7,002 of which had EST splice site confirmation and 7,224 had at least partial EST overlap. The MAKER-produced gene annotations were used for further downstream review and manual curation of over 500 genes across 16 gene categories (Table S1). Significant findings from this annotation are highlighted below, with additional details of our full analysis described in Text S1, S2, S3, S4, S5, S6, S7, S8, S9, S10, S11, S12, S13, S14, S15, S16, S17, S18, S19, S20).

In addition to the A. cephalotes genome sequence, we also recovered an 18-20X coverage complete and circular mitochondrial genome, which showed strong whole sequence identity to the mitochondrial genome sequence reported for the solitary wasp Diadegma semiclausum [33]. A synteny analysis of the predicted genes on the A. cephalotes mitochondrial genome showed near-identical gene order with that of A. mellifera [34] (Text S4).

Repetitive DNA

The A. cephalotes assembly contains 80 Mbp of repetitive elements, which accounts for 25% of the predicted assembly (Table S2). The large majority of these are interspersed repeats, which account for 70 Mbp (21%). Many of these repeats are transposable elements (TEs), with DNA TEs the most abundant and accounting for 14.3 Mbp (4.5%). A large number of retroid element fragments were also identified, with Gypsy/DIRS1 and L2/CR1/Rex as the most abundant. However, the majority of interspersed elements (51.8 Mbp) were similar to de novo predictions that we could not be classified to a specific family (Table S2). Improvements to the assembly, integration of repeat annotation evidence, and manual curation will be necessary to determine if these elements represent new TE families or complex nests of interspersed repeats.

Given the obligate association between A. cephalotes and its fungal cultivar, we investigated the possibility that the A. cephalotes genome might contain transposable elements commonly found in fungi. This was done by re-analyzing the genome using a TE library optimized for the detection of Fungi and Viridiplantae. We did not find evidence for any high-scoring or full-length retroid or DNA TEs from either of these taxa present in the A. cephalotes genome.

Our estimate that 25% of A. cephalotes assembly contains repetitive elements may be ambiguous because our assembly spans 317 Mbp and the estimated genome size for A. cephalotes is 300 Mbp [30]. These predictions are, however, more similar to other ant species [27] and N. vitripennis [35] than to A. mellifera [28], which lacks the majority of retroid elements and other transposable elements (TE) found in A. cephalotes.

Global Compositional Analysis

Eukaryotic genomes can be understood from the perspective of their nucleotide topography, particularly with respect to their GC content. Previous work has shown that animal genomes are not uniform, but are composed of compositional domains including homogeneous and nonhomogeneous stretches of DNA with varying GC composition [36]. A global composition analysis was performed for A. cephalotes and the compositional distribution was compared to those of other insect genomes, as described in Text S5. This analysis revealed that A. cephalotes has a compositional distribution similar to other animal genomes, with an abundance of short domain sequences and few long domain sequences. A. cephalotes also has the largest number of long GC-rich domain sequences when compared to other insect genomes, with over six times the number of long GC-rich domain sequences than the N. vitripennis genome. When genes are mapped to compositional domains in the A. cephalotes genome, we find that they are uniformly distributed across the entire genome, in contrast to N. vitripennis and A. mellifera, which have genes occurring in more GC-poor regions of their genomes.

DNA Methylation

The methylation of genes has been reported for other hymenopterans including A. mellifera [37] and N. vitripennis [35]. In insects, it is thought that this process contributes to gene silencing [37], but recent reports suggest a positive correlation between DNA methylation and gene expression [38], [39]. DNA methylation is thought to involve three genes: dnmt1, dnmt2, and dnmt3 [40], although the precise role of dnmt2 remains unresolved. We found all three genes as single copies in A. cephalotes, which is similar to the other ants [27] but in contrast to A. mellifera and N. vitripennis where dnmt1 has expanded to two and three copies, respectively [35] (Text S6). Dnmt3 is known to be involved in caste development in A. mellifera [41], and the presence of this gene in A. cephalotes may therefore indicate a similar role.

RNA interference is a mechanism through which the expression of RNA transcripts is modulated [42]. We annotated a total of 29 different RNAi-related genes in A. cephalotes, including most of the genes involved in the microRNA pathway, the small interfering RNA pathway, and the piwi-interacting RNA pathway (Text S7). All detected RNAi genes were found as single copies except for two copies of the gene loquacious. One of these contains three double-stranded RNA binding domains characteristic of loquacious in D. melanogaster [43], whereas the other contains only two. It is not known what role this second loquacious-like gene plays in A. cephalotes and future work is needed to deduce its role.

The Insulin Signaling Pathway

The insulin signaling pathway is a highly-conserved system in insects that plays a key role in many processes including metabolism, reproduction, growth, and aging [44]. An analysis of the insulin signaling system in A. cephalotes reveals that it has all of the core genes known to participate in this pathway (Text S8). One of the hallmarks of A. cephalotes biology is its complex size-based caste system and, although virtually nothing is known about the genetic basis of caste development in this ant, it is currently thought that it is intrinsically linked to brood care and the amount of nutrients fed to developing larvae [1]. Given the importance of the insulin signaling system in nutrition, it is likely that this pathway is involved in caste differentiation in A. cephalotes, as has been shown for A. mellifera [45].

Yellow and Major Royal Jelly Proteins

The yellow/major royal jelly proteins are encoded by an important class of genes and in A. mellifera they are thought to be integral to many major aspects of eusocial behavior [46]. For example, members of these genes are implicated in both caste development and sex determination. An analysis of this gene family in A. cephalotes revealed a total of 21 genes, 13 of which belong to the yellow genes and 8 of which encode major royal jelly proteins (MRJP) (Text S9). In general, the yellow genes display one-to-one orthology with yellow genes in other insects like Drosophila melanogaster and N. vitripennis. With eight members in the MRJP subfamily, which is restricted to Hymenoptera, the number of MRJP genes in A. cephalotes is similar to the number reported for other Hymenoptera [35], [46]. However, five of the eight genes in A. cephalotes are putative pseudogenes. This may indicate that a high copy number of MRJPs may be an ancestral feature and that Atta is in the process of losing these genes. The loss of MRJPs may be a common theme among ants, as the recently reported genome sequences for C. floridanus and H. saltator revealed only one and two MRJP genes, respectively [27].

Wing Polyphenism

Wing polyphenism is a universal feature of ants that has contributed to their evolutionary success [1]. The gene network that underlies wing polyphenism in ants responds to environmental cues such that this network is normally expressed in winged queens and males, but is interrupted at specific points in wingless workers [47]. We therefore predict that the differential expression of this network between queens and workers may be regulated by epigenetic mechanisms as has been demonstrated in honey bees [41]. In A. mellifera, developmental and caste specific genes have a distinct DNA methylation signature (high-CpG dinucleotide content) relative to other genes in the genome [48]. Because A. cephalotes has more worker castes than other ant species [23] (Figure 1C), we predict that the DNA methylation signature of genes underlying wing polyphenism will also be distinct relative to other genes in its genome. To test this prediction, we analyzed the sequence composition of wing development genes in A. cephalotes, and found that they exhibit a higher CpG dinucleotide content than the rest of the genes in the genome (Text S10). Previous experiments have shown that genes with a high-CpG dinucleotide content can be differentially methylated in specific tissues or different developmental stages [49]. Therefore, DNA methylation may facilitate the caste-specific expression of genes that underlie wing polyphenism in A. cephalotes. This may be a general feature of genes that underlie polyphenism.

Desaturases

An important aspect of the eusocial lifestyle is communication between colony members, specifically in differentiating between individuals that belong to the same colony and those that do not. Nestmate recognition in many ants is mediated by cuticular hydrocarbons (CHCs) [50], and nearly 1,000 of these compounds have been described. In ants, CHC biosynthesis involves Δ9/Δ11 desaturases, which are known to produce alkene components of CHC profiles [51]. We analyzed the Δ9 desaturases in the genome of A. cephalotes and detected nine genes localized to a 200 kbp stretch on a single scaffold in addition to four other Δ9 desaturase genes on other scaffolds (Text S11). In contrast, the seven genes found in D. melanogaster are more widely distributed along one chromosome. The number of Δ9 desaturase genes in A. cephalotes is similar to the 9 and 16 found in A. mellifera and N. vitripennis, respectively. A phylogenetic analysis of these genes supports their division into five clades, with eight Δ9 desaturase genes falling in a single clade suggesting an expansion of these genes possibly related to an increased demand for chemical signal variability during ant evolution (Text S11). Interestingly, the phylogeny also supports an expansion in this type of Δ9 desaturase genes within N. vitripennis but not in A. mellifera.

Immune Response

All insects have innate immune defenses to deal with potential pathogens [52] and A. cephalotes is no exception with a total of 84 annotated genes found to be involved in this response (Text S12). These include the intact immune signaling pathways Toll, Imd, Jak/Stat, and JNK. When compared to solitary insects like D. melanogaster and N. vitripennis, A. cephalotes has fewer immune response genes and better resembles what is known for the eusocial A. mellifera [53]. The presence of other defenses in A. cephalotes, such as antibiotics produced by metapleural glands [54]–[56], may account for the paucity of immune genes. Furthermore, social behavioral defenses may also participate in the immune response, as has been suggested for A. mellifera [53].

Orthology Analysis

A set of shared orthologs was determined among A. cephalotes, A. mellifera, N. vitripennis, and D. melanogaster (Figure 2). A total of 5,577 orthologs were found conserved across all four insect genomes, with an additional 1,363 orthologs conserved across the three hymenopteran genomes. A further, 599 orthologs were conserved between A. cephalotes and A. mellifera, perhaps indicating genes that are specific to a eusocial lifestyle. We also found 9,361 proteins that are unique to A. cephalotes, representing over half of its predicted proteome. These proteins likely include those specific to ants or to A. cephalotes.

We then analyzed the proteins that were found to be specific to A. cephalotes and determined those Gene Ontology (GO) [57] terms that are enriched in these proteins, relative to the rest of the genome (Table S3). We found many GO terms that reflect the biology of A. cephalotes and ants in general. For example, we find proteins with GO terms that reflect the importance of communication. These include proteins associated with olfactory receptor activity, odorant binding function, sensory perception, neurological development, localization at the synapse, and functions involved in ligand-gated and other membrane channels.

Gene Comparisons within Hymenopteran Genomes

To focus on Hymenoptera evolution, we compared the A. cephalotes genome to 4 other hymenopterans including the ants C. floridanus and H. saltator, the honey bee A. mellifera, and the solitary parasitic jewel wasp N. vitripennis. We used the eukaryotic clusters of orthologous groups (KOG) ontology [58] to annotate the predicted proteins from all of these genomes and performed an enrichment analysis by comparing the KOGs of the social insects A. cephalotes, C. floridanus, H. saltator, and A. mellifera against the KOGs of the non-social N. vitripennis as shown in Table S4.

A detailed analysis of KOGs within each over- and under-represented category is highly suggestive of A. cephalotes biology (Table S5). One of the most over-represented KOGs in A. cephalotes includes the 69 copies of the RhoA GTPase effector diaphanous (KOG1924). In contrast, all of the other hymenopteran genomes have substantially less copies of this gene. RhoA GTPase diaphanous is known to be involved in actin cytoskeleton organization and is essential for all actin-mediated events [59]. The large number of these genes in A. cephalotes may relate to the extensive cytoskeletal changes that occur during caste differentiation. One of these genes (ACEP_00016791) was found to exhibit high single nucleotide polymorphism (SNPs) (Text S13). Given that genes involved in caste development in other social insects like A. mellifera also have high SNPs [60], [61], this may indicate that this gene is important for caste determination in A. cephalotes. A. cephalotes is also significantly over-represented in the dosage compensation complex subunit (KOG0921), the homeobox transcription factor SIP1 (KOG3623), the muscarine acetylcholine receptor (KOG4220), the cadhedrin EGF LAG seven-pass GTP-type receptor (KOG4289), and the calcium-activated potassium channel slowpoke (KOG1420), relative to N. vitripennis. Many of these genes have been implicated in D. melanogaster larval development, specifically during nervous system formation [62], [63]. As a result, an over-representation of these genes in A. cephalotes relative to N. vitripennis may indicate their association with a eusocial lifestyle, and in particular, caste and subcaste differentiation.

Genes that were found to be under-represented in A. cephalotes relative to N. vitripennis include core histone genes, nucleosome-binding factor genes, serine protease trypsins, and cytochrome P450s (Table S5). These findings were confirmed by a domain-based comparison between A. cephalotes and all other sequenced insects (Text S14). One of the most under-represented KOGs is trypsin, a serine protease used in the degradation of proteins into their amino acid constituents. Trypsins in N. vitripennis are known to be part of the venom cocktail injected into its host, which helps necrotization and initiates the process of amino acid acquisition for developing larvae [35], [64]. In contrast to the protein-rich diet of N. vitripennis, A. cephalotes feed on gongylidia produced by their fungus, which represents a switch to a carbohydrate-rich (60% of mixture) diet [65]. These differences in diet may explain the under-representation of trypsin in A. cephalotes, as trypsin is likely not the primary mechanism used to digest nutrients obtained from the fungal cultivar. Our analysis also revealed a reduction of trypsin genes in the other social insects relative to N. vitripennis, and this may also reflect their diets. For example, honey dew is a major component of the diet of C. floridanus and contains primarily sugars [1], while the honey/pollen diet of A. mellifera is composed primarily of carbohydrates, lipids, carbohydrates, vitamins, and some proteins [66]. Because this under-representation of trypsin is consistent across social insects when compared to other sequenced insects (Table S5, Text S14), this reduction may reflect the specific dietary features of these insects, or could indicate a loss of these genes across eusocial insects.

In addition to trypsin, cytochrome P450s were also found to be under-represented in both A. cephalotes and A. mellifera, relative to N. vitripennis, with reductions in both CYP3- and CYP4-type P450s (Table S5). P450s in insects are important enzymes known to be involved in a wide range of metabolic activities, including xenobiotic degradation, and pheromone metabolism [67]. We identified a total of 52 and 62 P450s in A. cephalotes and A. mellifera, respectively, which is similar to the low numbers reported for another insect, the body louse Pediculus humanus [29]. These values represent some of the smallest amounts of P450s reported for any insect genome, and may represent the minimal number of P450s required by insects to survive. Comparison of the A. cephalotes P450s against those of A. mellifera and P. humanus reveals that while there are some shared P450s, many are specific to each insect (15).

In A. mellifera, the paucity of P450s is thought to be associated with the evolutionary underpinnings of its eusocial lifestyle [68], although an enrichment of P450s in the ants C. floridanus and H. saltator [27] would seem to contradict this prediction. It is therefore unclear why A. cephalotes has a small number of P450s relative to other ants, and future work will be necessary to provide insight into this apparent discrepancy. A SNP analysis of the P450 genes in A. cephalotes did reveal that one of these, ACEP_00016463, has 20 SNPs/kbp (Text S13). Since P450s are known to undergo accelerated duplication and divergence [67], the high number of SNPs in this particular P450 may reflect positive selection for new functions.

Comparative Metabolic Reconstruction Analysis

Given the tight obligate association that A. cephalotes has with its fungal mutualist, one might predict that it acquires amino acids from its fungus in a manner similar to that of the pea aphid Acyrthosiphon pisum, which obtains amino acids from its bacterial symbionts [28]. To test this, we performed a metabolic reconstruction analysis using the Kyoto Encyclopedia of Genes and Genomes (KEGG) [69]. A. cephalotes contains a nearly identical set of amino acid biosynthesis genes as A. mellifera, C. floridanus, H. saltator, and N. vitripennis, all of which are incapable of synthesizing histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan, and valine de novo. The only exception is arginine, and only A. cephalotes was found to lack the genes necessary for its biosynthesis (Figure 3). Arginine, which is produced through the conversion of citrulline and aspartate [70], [71], is predicted to be synthesized at levels too low to support growth in insects [72].


Watch the video: Jack Jumper venomous ant stings


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